openssl/1.0.2p/INSTALL


 INSTALLATION ON THE UNIX PLATFORM
 ---------------------------------

 [Installation on DOS (with djgpp), Windows, OpenVMS, MacOS (before MacOS X)
  and NetWare is described in INSTALL.DJGPP, INSTALL.W32, INSTALL.VMS,
  INSTALL.MacOS and INSTALL.NW.
  
  This document describes installation on operating systems in the Unix
  family.]

 To install OpenSSL, you will need:

  * make
  * Perl 5
  * an ANSI C compiler
  * a development environment in form of development libraries and C
    header files
  * a supported Unix operating system

 Quick Start
 -----------

 If you want to just get on with it, do:

  $ ./config
  $ make
  $ make test
  $ make install

 [If any of these steps fails, see section Installation in Detail below.]

 This will build and install OpenSSL in the default location, which is (for
 historical reasons) /usr/local/ssl. If you want to install it anywhere else,
 run config like this:

  $ ./config --prefix=/usr/local --openssldir=/usr/local/openssl


 Configuration Options
 ---------------------

 There are several options to ./config (or ./Configure) to customize
 the build:

  --prefix=DIR  Install in DIR/bin, DIR/lib, DIR/include/openssl.
                Configuration files used by OpenSSL will be in DIR/ssl
                or the directory specified by --openssldir.

  --openssldir=DIR Directory for OpenSSL files. If no prefix is specified,
                the library files and binaries are also installed there.

  no-threads    Don't try to build with support for multi-threaded
                applications.

  threads       Build with support for multi-threaded applications.
                This will usually require additional system-dependent options!
                See "Note on multi-threading" below.

  no-zlib       Don't try to build with support for zlib compression and
                decompression.

  zlib          Build with support for zlib compression/decompression.

  zlib-dynamic  Like "zlib", but has OpenSSL load the zlib library dynamically
                when needed.  This is only supported on systems where loading
                of shared libraries is supported.  This is the default choice.

  no-shared     Don't try to create shared libraries.

  shared        In addition to the usual static libraries, create shared
                libraries on platforms where it's supported.  See "Note on
                shared libraries" below.

  no-asm        Do not use assembler code.

  386           In 32-bit x86 builds, when generating assembly modules,
                use the 80386 instruction set only (the default x86 code
                is more efficient, but requires at least a 486). Note:
                This doesn't affect code generated by compiler, you're
                likely to complement configuration command line with
                suitable compiler-specific option.

  no-sse2       Exclude SSE2 code paths from 32-bit x86 assembly modules.
                Normally SSE2 extension is detected at run-time, but the
                decision whether or not the machine code will be executed
                is taken solely on CPU capability vector. This means that
                if you happen to run OS kernel which does not support SSE2
                extension on Intel P4 processor, then your application
                might be exposed to "illegal instruction" exception.
                There might be a way to enable support in kernel, e.g.
                FreeBSD kernel can  be compiled with CPU_ENABLE_SSE, and
                there is a way to disengage SSE2 code paths upon application
                start-up, but if you aim for wider "audience" running
                such kernel, consider no-sse2. Both the 386 and
                no-asm options imply no-sse2.

  no-<cipher>   Build without the specified cipher (bf, cast, des, dh, dsa,
                hmac, md2, md5, mdc2, rc2, rc4, rc5, rsa, sha).
                The crypto/<cipher> directory can be removed after running
                "make depend".

  -Dxxx, -lxxx, -Lxxx, -fxxx, -mXXX, -Kxxx These system specific options will
                be passed through to the compiler to allow you to
                define preprocessor symbols, specify additional libraries,
                library directories or other compiler options. It might be
                worth noting that some compilers generate code specifically
                for processor the compiler currently executes on. This is
                not necessarily what you might have in mind, since it might
                be unsuitable for execution on other, typically older,
                processor. Consult your compiler documentation.

  -DHAVE_CRYPTODEV Enable the BSD cryptodev engine even if we are not using
                BSD. Useful if you are running ocf-linux or something
                similar. Once enabled you can also enable the use of
                cryptodev digests, which is usually slower unless you have
                large amounts data. Use -DUSE_CRYPTODEV_DIGESTS to force
                it.

 Installation in Detail
 ----------------------

 1a. Configure OpenSSL for your operation system automatically:

       $ ./config [options]

     This guesses at your operating system (and compiler, if necessary) and
     configures OpenSSL based on this guess. Run ./config -t to see
     if it guessed correctly. If you want to use a different compiler, you
     are cross-compiling for another platform, or the ./config guess was
     wrong for other reasons, go to step 1b. Otherwise go to step 2.

     On some systems, you can include debugging information as follows:

       $ ./config -d [options]

 1b. Configure OpenSSL for your operating system manually

     OpenSSL knows about a range of different operating system, hardware and
     compiler combinations. To see the ones it knows about, run

       $ ./Configure

     Pick a suitable name from the list that matches your system. For most
     operating systems there is a choice between using "cc" or "gcc".  When
     you have identified your system (and if necessary compiler) use this name
     as the argument to ./Configure. For example, a "linux-elf" user would
     run:

       $ ./Configure linux-elf [options]

     If your system is not available, you will have to edit the Configure
     program and add the correct configuration for your system. The
     generic configurations "cc" or "gcc" should usually work on 32 bit
     systems.

     Configure creates the file Makefile.ssl from Makefile.org and
     defines various macros in crypto/opensslconf.h (generated from
     crypto/opensslconf.h.in).

  2. Build OpenSSL by running:

       $ make

     This will build the OpenSSL libraries (libcrypto.a and libssl.a) and the
     OpenSSL binary ("openssl"). The libraries will be built in the top-level
     directory, and the binary will be in the "apps" directory.

     If the build fails, look at the output.  There may be reasons
     for the failure that aren't problems in OpenSSL itself (like
     missing standard headers).  If you are having problems you can
     get help by sending an email to the openssl-users email list (see
     https://www.openssl.org/community/mailinglists.html for details). If
     it is a bug with OpenSSL itself, please open an issue on GitHub, at
     https://github.com/openssl/openssl/issues. Please review the existing
     ones first; maybe the bug was already reported or has already been
     fixed.

     (If you encounter assembler error messages, try the "no-asm"
     configuration option as an immediate fix.)

     Compiling parts of OpenSSL with gcc and others with the system
     compiler will result in unresolved symbols on some systems.

  3. After a successful build, the libraries should be tested. Run:

       $ make test

     If a test fails, look at the output.  There may be reasons for
     the failure that isn't a problem in OpenSSL itself (like a missing
     or malfunctioning bc).  If it is a problem with OpenSSL itself,
     try removing any compiler optimization flags from the CFLAG line
     in Makefile.ssl and run "make clean; make". To report a bug please open an
     issue on GitHub, at https://github.com/openssl/openssl/issues.

  4. If everything tests ok, install OpenSSL with

       $ make install

     This will create the installation directory (if it does not exist) and
     then the following subdirectories:

       certs           Initially empty, this is the default location
                       for certificate files.
       man/man1        Manual pages for the 'openssl' command line tool
       man/man3        Manual pages for the libraries (very incomplete)
       misc            Various scripts.
       private         Initially empty, this is the default location
                       for private key files.

     If you didn't choose a different installation prefix, the
     following additional subdirectories will be created:

       bin             Contains the openssl binary and a few other 
                       utility programs. 
       include/openssl Contains the header files needed if you want to
                       compile programs with libcrypto or libssl.
       lib             Contains the OpenSSL library files themselves.

     Use "make install_sw" to install the software without documentation,
     and "install_docs_html" to install HTML renditions of the manual
     pages.

     Package builders who want to configure the library for standard
     locations, but have the package installed somewhere else so that
     it can easily be packaged, can use

       $ make INSTALL_PREFIX=/tmp/package-root install

     (or specify "--install_prefix=/tmp/package-root" as a configure
     option).  The specified prefix will be prepended to all
     installation target filenames.


  NOTE: The header files used to reside directly in the include
  directory, but have now been moved to include/openssl so that
  OpenSSL can co-exist with other libraries which use some of the
  same filenames.  This means that applications that use OpenSSL
  should now use C preprocessor directives of the form

       #include <openssl/ssl.h>

  instead of "#include <ssl.h>", which was used with library versions
  up to OpenSSL 0.9.2b.

  If you install a new version of OpenSSL over an old library version,
  you should delete the old header files in the include directory.

  Compatibility issues:

  *  COMPILING existing applications

     To compile an application that uses old filenames -- e.g.
     "#include <ssl.h>" --, it will usually be enough to find
     the CFLAGS definition in the application's Makefile and
     add a C option such as

          -I/usr/local/ssl/include/openssl

     to it.

     But don't delete the existing -I option that points to
     the ..../include directory!  Otherwise, OpenSSL header files
     could not #include each other.

  *  WRITING applications

     To write an application that is able to handle both the new
     and the old directory layout, so that it can still be compiled
     with library versions up to OpenSSL 0.9.2b without bothering
     the user, you can proceed as follows:

     -  Always use the new filename of OpenSSL header files,
        e.g. #include <openssl/ssl.h>.

     -  Create a directory "incl" that contains only a symbolic
        link named "openssl", which points to the "include" directory
        of OpenSSL.
        For example, your application's Makefile might contain the
        following rule, if OPENSSLDIR is a pathname (absolute or
        relative) of the directory where OpenSSL resides:

        incl/openssl:
                -mkdir incl
                cd $(OPENSSLDIR) # Check whether the directory really exists
                -ln -s `cd $(OPENSSLDIR); pwd`/include incl/openssl

        You will have to add "incl/openssl" to the dependencies
        of those C files that include some OpenSSL header file.

     -  Add "-Iincl" to your CFLAGS.

     With these additions, the OpenSSL header files will be available
     under both name variants if an old library version is used:
     Your application can reach them under names like <openssl/foo.h>,
     while the header files still are able to #include each other
     with names of the form <foo.h>.


 Note on multi-threading
 -----------------------

 For some systems, the OpenSSL Configure script knows what compiler options
 are needed to generate a library that is suitable for multi-threaded
 applications.  On these systems, support for multi-threading is enabled
 by default; use the "no-threads" option to disable (this should never be
 necessary).

 On other systems, to enable support for multi-threading, you will have
 to specify at least two options: "threads", and a system-dependent option.
 (The latter is "-D_REENTRANT" on various systems.)  The default in this
 case, obviously, is not to include support for multi-threading (but
 you can still use "no-threads" to suppress an annoying warning message
 from the Configure script.)


 Note on shared libraries
 ------------------------

 Shared libraries have certain caveats.  Binary backward compatibility
 can't be guaranteed before OpenSSL version 1.0.  The only reason to
 use them would be to conserve memory on systems where several programs
 are using OpenSSL.

 For some systems, the OpenSSL Configure script knows what is needed to
 build shared libraries for libcrypto and libssl.  On these systems,
 the shared libraries are currently not created by default, but giving
 the option "shared" will get them created.  This method supports Makefile
 targets for shared library creation, like linux-shared.  Those targets
 can currently be used on their own just as well, but this is expected
 to change in future versions of OpenSSL.

 Note on random number generation
 --------------------------------

 Availability of cryptographically secure random numbers is required for
 secret key generation. OpenSSL provides several options to seed the
 internal PRNG. If not properly seeded, the internal PRNG will refuse
 to deliver random bytes and a "PRNG not seeded error" will occur.
 On systems without /dev/urandom (or similar) device, it may be necessary
 to install additional support software to obtain random seed.
 Please check out the manual pages for RAND_add(), RAND_bytes(), RAND_egd(),
 and the FAQ for more information.

 Note on support for multiple builds
 -----------------------------------

 OpenSSL is usually built in its source tree.  Unfortunately, this doesn't
 support building for multiple platforms from the same source tree very well.
 It is however possible to build in a separate tree through the use of lots
 of symbolic links, which should be prepared like this:

        mkdir -p objtree/"`uname -s`-`uname -r`-`uname -m`"
        cd objtree/"`uname -s`-`uname -r`-`uname -m`"
        (cd $OPENSSL_SOURCE; find . -type f) | while read F; do
                mkdir -p `dirname $F`
                rm -f $F; ln -s $OPENSSL_SOURCE/$F $F
                echo $F '->' $OPENSSL_SOURCE/$F
        done
        make -f Makefile.org clean

 OPENSSL_SOURCE is an environment variable that contains the absolute (this
 is important!) path to the OpenSSL source tree.

 Also, operations like 'make update' should still be made in the source tree.
Revision:	12146
Committed:	Sat Jan 19 20:00:07 2019 UTC (5 years, 3 months ago) by laffer1
File size:	15214 byte(s)
Log Message:	tag 1.0.2p
#	Content
1
2	INSTALLATION ON THE UNIX PLATFORM
3	---------------------------------
4
5	[Installation on DOS (with djgpp), Windows, OpenVMS, MacOS (before MacOS X)
6	and NetWare is described in INSTALL.DJGPP, INSTALL.W32, INSTALL.VMS,
7	INSTALL.MacOS and INSTALL.NW.
8
9	This document describes installation on operating systems in the Unix
10	family.]
11
12	To install OpenSSL, you will need:
13
14	* make
15	* Perl 5
16	* an ANSI C compiler
17	* a development environment in form of development libraries and C
18	header files
19	* a supported Unix operating system
20
21	Quick Start
22	-----------
23
24	If you want to just get on with it, do:
25
26	$ ./config
27	$ make
28	$ make test
29	$ make install
30
31	[If any of these steps fails, see section Installation in Detail below.]
32
33	This will build and install OpenSSL in the default location, which is (for
34	historical reasons) /usr/local/ssl. If you want to install it anywhere else,
35	run config like this:
36
37	$ ./config --prefix=/usr/local --openssldir=/usr/local/openssl
38
39
40	Configuration Options
41	---------------------
42
43	There are several options to ./config (or ./Configure) to customize
44	the build:
45
46	--prefix=DIR Install in DIR/bin, DIR/lib, DIR/include/openssl.
47	Configuration files used by OpenSSL will be in DIR/ssl
48	or the directory specified by --openssldir.
49
50	--openssldir=DIR Directory for OpenSSL files. If no prefix is specified,
51	the library files and binaries are also installed there.
52
53	no-threads Don't try to build with support for multi-threaded
54	applications.
55
56	threads Build with support for multi-threaded applications.
57	This will usually require additional system-dependent options!
58	See "Note on multi-threading" below.
59
60	no-zlib Don't try to build with support for zlib compression and
61	decompression.
62
63	zlib Build with support for zlib compression/decompression.
64
65	zlib-dynamic Like "zlib", but has OpenSSL load the zlib library dynamically
66	when needed. This is only supported on systems where loading
67	of shared libraries is supported. This is the default choice.
68
69	no-shared Don't try to create shared libraries.
70
71	shared In addition to the usual static libraries, create shared
72	libraries on platforms where it's supported. See "Note on
73	shared libraries" below.
74
75	no-asm Do not use assembler code.
76
77	386 In 32-bit x86 builds, when generating assembly modules,
78	use the 80386 instruction set only (the default x86 code
79	is more efficient, but requires at least a 486). Note:
80	This doesn't affect code generated by compiler, you're
81	likely to complement configuration command line with
82	suitable compiler-specific option.
83
84	no-sse2 Exclude SSE2 code paths from 32-bit x86 assembly modules.
85	Normally SSE2 extension is detected at run-time, but the
86	decision whether or not the machine code will be executed
87	is taken solely on CPU capability vector. This means that
88	if you happen to run OS kernel which does not support SSE2
89	extension on Intel P4 processor, then your application
90	might be exposed to "illegal instruction" exception.
91	There might be a way to enable support in kernel, e.g.
92	FreeBSD kernel can be compiled with CPU_ENABLE_SSE, and
93	there is a way to disengage SSE2 code paths upon application
94	start-up, but if you aim for wider "audience" running
95	such kernel, consider no-sse2. Both the 386 and
96	no-asm options imply no-sse2.
97
98	no-<cipher> Build without the specified cipher (bf, cast, des, dh, dsa,
99	hmac, md2, md5, mdc2, rc2, rc4, rc5, rsa, sha).
100	The crypto/<cipher> directory can be removed after running
101	"make depend".
102
103	-Dxxx, -lxxx, -Lxxx, -fxxx, -mXXX, -Kxxx These system specific options will
104	be passed through to the compiler to allow you to
105	define preprocessor symbols, specify additional libraries,
106	library directories or other compiler options. It might be
107	worth noting that some compilers generate code specifically
108	for processor the compiler currently executes on. This is
109	not necessarily what you might have in mind, since it might
110	be unsuitable for execution on other, typically older,
111	processor. Consult your compiler documentation.
112
113	-DHAVE_CRYPTODEV Enable the BSD cryptodev engine even if we are not using
114	BSD. Useful if you are running ocf-linux or something
115	similar. Once enabled you can also enable the use of
116	cryptodev digests, which is usually slower unless you have
117	large amounts data. Use -DUSE_CRYPTODEV_DIGESTS to force
118	it.
119
120	Installation in Detail
121	----------------------
122
123	1a. Configure OpenSSL for your operation system automatically:
124
125	$ ./config [options]
126
127	This guesses at your operating system (and compiler, if necessary) and
128	configures OpenSSL based on this guess. Run ./config -t to see
129	if it guessed correctly. If you want to use a different compiler, you
130	are cross-compiling for another platform, or the ./config guess was
131	wrong for other reasons, go to step 1b. Otherwise go to step 2.
132
133	On some systems, you can include debugging information as follows:
134
135	$ ./config -d [options]
136
137	1b. Configure OpenSSL for your operating system manually
138
139	OpenSSL knows about a range of different operating system, hardware and
140	compiler combinations. To see the ones it knows about, run
141
142	$ ./Configure
143
144	Pick a suitable name from the list that matches your system. For most
145	operating systems there is a choice between using "cc" or "gcc". When
146	you have identified your system (and if necessary compiler) use this name
147	as the argument to ./Configure. For example, a "linux-elf" user would
148	run:
149
150	$ ./Configure linux-elf [options]
151
152	If your system is not available, you will have to edit the Configure
153	program and add the correct configuration for your system. The
154	generic configurations "cc" or "gcc" should usually work on 32 bit
155	systems.
156
157	Configure creates the file Makefile.ssl from Makefile.org and
158	defines various macros in crypto/opensslconf.h (generated from
159	crypto/opensslconf.h.in).
160
161	2. Build OpenSSL by running:
162
163	$ make
164
165	This will build the OpenSSL libraries (libcrypto.a and libssl.a) and the
166	OpenSSL binary ("openssl"). The libraries will be built in the top-level
167	directory, and the binary will be in the "apps" directory.
168
169	If the build fails, look at the output. There may be reasons
170	for the failure that aren't problems in OpenSSL itself (like
171	missing standard headers). If you are having problems you can
172	get help by sending an email to the openssl-users email list (see
173	https://www.openssl.org/community/mailinglists.html for details). If
174	it is a bug with OpenSSL itself, please open an issue on GitHub, at
175	https://github.com/openssl/openssl/issues. Please review the existing
176	ones first; maybe the bug was already reported or has already been
177	fixed.
178
179	(If you encounter assembler error messages, try the "no-asm"
180	configuration option as an immediate fix.)
181
182	Compiling parts of OpenSSL with gcc and others with the system
183	compiler will result in unresolved symbols on some systems.
184
185	3. After a successful build, the libraries should be tested. Run:
186
187	$ make test
188
189	If a test fails, look at the output. There may be reasons for
190	the failure that isn't a problem in OpenSSL itself (like a missing
191	or malfunctioning bc). If it is a problem with OpenSSL itself,
192	try removing any compiler optimization flags from the CFLAG line
193	in Makefile.ssl and run "make clean; make". To report a bug please open an
194	issue on GitHub, at https://github.com/openssl/openssl/issues.
195
196	4. If everything tests ok, install OpenSSL with
197
198	$ make install
199
200	This will create the installation directory (if it does not exist) and
201	then the following subdirectories:
202
203	certs Initially empty, this is the default location
204	for certificate files.
205	man/man1 Manual pages for the 'openssl' command line tool
206	man/man3 Manual pages for the libraries (very incomplete)
207	misc Various scripts.
208	private Initially empty, this is the default location
209	for private key files.
210
211	If you didn't choose a different installation prefix, the
212	following additional subdirectories will be created:
213
214	bin Contains the openssl binary and a few other
215	utility programs.
216	include/openssl Contains the header files needed if you want to
217	compile programs with libcrypto or libssl.
218	lib Contains the OpenSSL library files themselves.
219
220	Use "make install_sw" to install the software without documentation,
221	and "install_docs_html" to install HTML renditions of the manual
222	pages.
223
224	Package builders who want to configure the library for standard
225	locations, but have the package installed somewhere else so that
226	it can easily be packaged, can use
227
228	$ make INSTALL_PREFIX=/tmp/package-root install
229
230	(or specify "--install_prefix=/tmp/package-root" as a configure
231	option). The specified prefix will be prepended to all
232	installation target filenames.
233
234
235	NOTE: The header files used to reside directly in the include
236	directory, but have now been moved to include/openssl so that
237	OpenSSL can co-exist with other libraries which use some of the
238	same filenames. This means that applications that use OpenSSL
239	should now use C preprocessor directives of the form
240
241	#include <openssl/ssl.h>
242
243	instead of "#include <ssl.h>", which was used with library versions
244	up to OpenSSL 0.9.2b.
245
246	If you install a new version of OpenSSL over an old library version,
247	you should delete the old header files in the include directory.
248
249	Compatibility issues:
250
251	* COMPILING existing applications
252
253	To compile an application that uses old filenames -- e.g.
254	"#include <ssl.h>" --, it will usually be enough to find
255	the CFLAGS definition in the application's Makefile and
256	add a C option such as
257
258	-I/usr/local/ssl/include/openssl
259
260	to it.
261
262	But don't delete the existing -I option that points to
263	the ..../include directory! Otherwise, OpenSSL header files
264	could not #include each other.
265
266	* WRITING applications
267
268	To write an application that is able to handle both the new
269	and the old directory layout, so that it can still be compiled
270	with library versions up to OpenSSL 0.9.2b without bothering
271	the user, you can proceed as follows:
272
273	- Always use the new filename of OpenSSL header files,
274	e.g. #include <openssl/ssl.h>.
275
276	- Create a directory "incl" that contains only a symbolic
277	link named "openssl", which points to the "include" directory
278	of OpenSSL.
279	For example, your application's Makefile might contain the
280	following rule, if OPENSSLDIR is a pathname (absolute or
281	relative) of the directory where OpenSSL resides:
282
283	incl/openssl:
284	-mkdir incl
285	cd $(OPENSSLDIR) # Check whether the directory really exists
286	-ln -s `cd $(OPENSSLDIR); pwd`/include incl/openssl
287
288	You will have to add "incl/openssl" to the dependencies
289	of those C files that include some OpenSSL header file.
290
291	- Add "-Iincl" to your CFLAGS.
292
293	With these additions, the OpenSSL header files will be available
294	under both name variants if an old library version is used:
295	Your application can reach them under names like <openssl/foo.h>,
296	while the header files still are able to #include each other
297	with names of the form <foo.h>.
298
299
300	Note on multi-threading
301	-----------------------
302
303	For some systems, the OpenSSL Configure script knows what compiler options
304	are needed to generate a library that is suitable for multi-threaded
305	applications. On these systems, support for multi-threading is enabled
306	by default; use the "no-threads" option to disable (this should never be
307	necessary).
308
309	On other systems, to enable support for multi-threading, you will have
310	to specify at least two options: "threads", and a system-dependent option.
311	(The latter is "-D_REENTRANT" on various systems.) The default in this
312	case, obviously, is not to include support for multi-threading (but
313	you can still use "no-threads" to suppress an annoying warning message
314	from the Configure script.)
315
316
317	Note on shared libraries
318	------------------------
319
320	Shared libraries have certain caveats. Binary backward compatibility
321	can't be guaranteed before OpenSSL version 1.0. The only reason to
322	use them would be to conserve memory on systems where several programs
323	are using OpenSSL.
324
325	For some systems, the OpenSSL Configure script knows what is needed to
326	build shared libraries for libcrypto and libssl. On these systems,
327	the shared libraries are currently not created by default, but giving
328	the option "shared" will get them created. This method supports Makefile
329	targets for shared library creation, like linux-shared. Those targets
330	can currently be used on their own just as well, but this is expected
331	to change in future versions of OpenSSL.
332
333	Note on random number generation
334	--------------------------------
335
336	Availability of cryptographically secure random numbers is required for
337	secret key generation. OpenSSL provides several options to seed the
338	internal PRNG. If not properly seeded, the internal PRNG will refuse
339	to deliver random bytes and a "PRNG not seeded error" will occur.
340	On systems without /dev/urandom (or similar) device, it may be necessary
341	to install additional support software to obtain random seed.
342	Please check out the manual pages for RAND_add(), RAND_bytes(), RAND_egd(),
343	and the FAQ for more information.
344
345	Note on support for multiple builds
346	-----------------------------------
347
348	OpenSSL is usually built in its source tree. Unfortunately, this doesn't
349	support building for multiple platforms from the same source tree very well.
350	It is however possible to build in a separate tree through the use of lots
351	of symbolic links, which should be prepared like this:
352
353	mkdir -p objtree/"`uname -s`-`uname -r`-`uname -m`"
354	cd objtree/"`uname -s`-`uname -r`-`uname -m`"
355	(cd $OPENSSL_SOURCE; find . -type f) \| while read F; do
356	mkdir -p `dirname $F`
357	rm -f $F; ln -s $OPENSSL_SOURCE/$F $F
358	echo $F '->' $OPENSSL_SOURCE/$F
359	done
360	make -f Makefile.org clean
361
362	OPENSSL_SOURCE is an environment variable that contains the absolute (this
363	is important!) path to the OpenSSL source tree.
364
365	Also, operations like 'make update' should still be made in the source tree.