Optimizations for APM's xgene-1 (aarch64).
1) general system updates to support armv8 better. Make all did not work, one needed to supply TARGET=ARMV8.
2) sgem 4x4 kernel in assembler using SIMD, and configuration changes to use it.
3) strmm 4x4 kernel in C. Since the sgem kernel does 4x4, the trmm kernel must also do 4xN.
Added Dave Nuechterlein to the contributors list.
get_nprocs() is a GNU convenience function equivalent to POSIX2008
sysconf(_SC_NPROCESSORS_ONLN); the latter should be available in unistd.h
on any current *nix. (OS X supports this call since 10.5, and FreeBSD
currently supports it. But this commit does not change FreeBSD or OS X
versions.)
Benedikt Huber
Isaac Dunham
Timothy Gu
Zhang Xianyi