Move define adjustments to CPPFLAGS.
Adjust user CFLAGS directly, do not override during configuration.
USER_CFLAGS is not necessary to build libcompat_noopt correctly.
This adds initial support for assembly crypto acceleration on x86_64 for
ELF (Linux, *BSD, Solaris) and Mach-O (OS-X) systems.
The build method is a little different than OpenSSL and OpenBSD. All
the .s files are generated ahead of time when the tarball is generated,
so there are no complicated makefile rules at configure/build time. This
also means the builds are faster and perl is not required on the build
system.
Thanks to Wouter Clarie for providing the initial cleanup and patch
that this is based on.
