NOTES.UNIX

 NOTES FOR UNIX LIKE PLATFORMS
 =============================

 For Unix/POSIX runtime systems on Windows, please see NOTES.WIN.


 Shared libraries and installation in non-standard locations
 -----------------------------------------------------------

 Binaries on Unix variants expect to find shared libraries in standard
 locations, such as /usr/lib, /usr/local/lib and some other locations
 configured in the system (for example /etc/ld.so.conf on some systems).
 If the libraries are installed in non-standard locations, binaries
 will not find them and therefore fail to run unless they get a bit of
 help from a defined RPATH or RUNPATH.  This can be applied by adding
 the appropriate linker flags to the configuration command, such as
 this (/usr/local/ssl was the default location for OpenSSL installation
 in versions before 1.1.0):

    $ ./config --prefix=/usr/local/ssl --openssldir=/usr/local/ssl \
        -Wl,-rpath,/usr/local/ssl/lib

 Because the actual library location may vary further (for example on
 multilib installations), there is a convenience variable in Makefile
 that holds the exact installation directory and that can be used like
 this:

    $ ./config --prefix=/usr/local/ssl --openssldir=/usr/local/ssl \
        -Wl,-rpath,'$(LIBRPATH)'

 On modern systems using GNU ld.so, a better choice may be to use the
 new dtags, like this:

    $ ./config --prefix=/usr/local/ssl --openssldir=/usr/local/ssl \
        -Wl,--enable-new-dtags,-rpath,'$(LIBRPATH)'

 This sets DT_RUNPATH instead of DT_RPATH.  DT_RUNPATH is considered after
 the environment variable LD_LIBRARY_PATH, while DT_RPATH is considered
 before that environment variable (which means that the values in that
 environment variable won't matter if the library is found in the
 paths given by DT_RPATH).