Commit d512b25f69 introduced a crypto
library abstraction in the autotools build system, to allow us to more
easily support new crypto libraries. In that process it was found that
all other build system which we support are hard-coded to build with
OpenSSL. Commit f5c1a0d98b fixes automake
introduced into non-autotools build systems but still overlooked the
CPP macro saying that we are using OpenSSL.
Thanks to Marc Hörsken for identifying this issue and proposing a fix
for win32/{GNUmakefile,config.mk}. This commit uses a slightly different
approach but the end result is the same.
Commit d512b25f69 added automake
conditionals to Makefile.inc but since Makefile.inc is included
from Makefile for all other build systems that does not work.
This commit instead adds Makefile.OpenSSL.inc and Makefile.libgcrypt.inc
and moves the automake conditional to its proper place, src/Makefile.am.
The automake conditional includes the correct Makefile.$name.inc per
the crypto library selection/detection done by configure.
All non-autotools build system files in libssh2 are hardcoded to use
OpenSSL and do not get a conditional but at least there is some reuse
because they can all include the new Makefile.OpenSSL.inc.
