Introduce support for using OpenSSL ASM optimizations. This is done

through the use of a new build directive, MACHINE_CPU, which contains a
list of the CPU generations/features for which optimizations are desired.
This feature will be extended to cover the ports tree in the future.

Currently OpenSSL provides optimizations for i386, i586 and i686-class
CPUs. Currently it has not been tested on an i386 or i486.

Teach make(1) to provide sensible defaults for MACHINE_CPU if it is not
defined (namely, the lowest common denominator CPU we support for each
architecture).  Currently this is i386 for the i386 architecture and ev4
for the alpha.  sys.mk also sets the variable as a last resort for
consistency with MACHINE_ARCH and bootstrapping from very old versions of
make.

Benchmarks show a significant speed increase even in the i386 case, with
additional improvements for i586 and i686 systems.  For maximum performance
define MACHINE_CPU=i686 i586 i386 in /etc/make.conf.

Based on a patch submitted by:  Mike Silbersack <silby@silby.com>
Reviewed by:    current

1 files changed, 3 insertions, 1 deletions

diff --git a/share/mk/sys.mk b/share/mk/sys.mk
index 1449d99..11d6002 100644
--- a/share/mk/sys.mk
+++ b/share/mk/sys.mk
@@ -101,8 +101,10 @@ YFLAGS		?=	-d
 # which knows MACHINE, but not MACHINE_ARCH. When building on other
 # architectures, assume that the version of make being used has an
 # explicit MACHINE_ARCH setting and treat a missing MACHINE_ARCH
-# as an i386 architecture.
+# as an i386 architecture. Similarly for MACHINE_CPU, which indicates
+# the specific CPU generation to use, for optimization purposes.
 MACHINE_ARCH	?=	i386
+MACHINE_CPU	?=	i386
 
 # For tags rule.
 GTAGSFLAGS=	-o