OpenSSL is one of those packages that often have alternatives
with later versions. For instance, CentOS/EL 7 has an
openssl package at version 1.0.2 but there's an openssl11
package from the epel repository that has 1.1.1. This gets
installed to /usr/include/openssl11 and /usr/lib64/openssl11.
Unfortunately, the existing --with-ssl and --with-crypto
./configure options expect to point to a source tree and
don't work in this situation. Also unfortunately, the
checks in ./configure don't use pkg-config.
In order to make this work with the existing situation, you'd
have to run...
./configure --with-ssl=/usr/lib64/openssl11 \
--with-crypto=/usr/lib64/openssl11 \
CFLAGS=-I/usr/include/openssl11
BUT... those options don't get passed down to bundled pjproject
so when you run make, you have to include the CFLAGS again
which is a big pain.
Oh... To make matters worse, although you can specify
PJPROJECT_CONFIGURE_OPTS on the ./configure command line,
they don't get saved so if you do a make clean, which will
force a re-configure of bundled pjproject, those options
don't get used.
So...
* In configure.ac... Since pkg-config is installed by install_prereq
anyway, we now use it to check for the system openssl >= 1.1.0.
If that works, great. If not, we check for the openssl11
package. If that works, great. If not, we fall back to just
checking for any openssl. If pkg-config isn't installed for some
reason, or --with-ssl=<dir> or --with-crypto=<dir> were specified
on the ./configure command line, we fall back to the existing
logic that uses AST_EXT_LIB_CHECK().
* The whole OpenSSL check process has been moved up before
THIRD_PARTY_CONFIGURE(), which does the initial pjproject
bundled configure, is run. This way the results of the above
checks, which may result in new include or library directories,
is included.
* Although not strictly needed for openssl, We now save the value of
PJPROJECT_CONFIGURE_OPTS in the makeopts file so it can be used
again if a re-configure is triggered.
ASTERISK-29693
Change-Id: I341ab7603e6b156aa15a66f43675ac5029d5fbde
c07e3c2f4d