[WIP] Use arm neon instructions to optimize gemm beta operation

driver: more reasonable thread wait timeout on Windows.

It used to be 5ms, which might not be long enough in some cases for the
thread to exit well, but then when set to 5000 (5s), it would slow down
any program depending on OpenBlas.

Let's just set it to 50ms, which is at least 10 times longer than
originally, but still reasonable in case of failed thread termination.

Changes to build on AIX in POWER8 mode

Support two-digit version numbers in gcc version check

fixes #2336 (non-recognition of gcc 10) with patch provided by JeffreyALaw.

* Update DYNAMIC_ARCH list of ARM64 targets for gmake
* Update arm64 cpu list for runtime detection
* Update DYNAMIC_ARCH list of ARM64 targets for cmake and add POWERPC targets

Remove misplaced file

was originally in #2228 but that PR had misplaced the file in the toplevel directory

Rebase

Workaround an ICE in clang 9.0.0

This bug is not there in 8.x nor in the 9.0 daily snapshot.

Fix precompiled kernels on POWER9 and make their use conditional on (old) gcc version

Fix SEGV in cdot_power9

used in KERNEL.POWER9

rebase

some optimizations of AVX512 DGEMM

Fix race conditions in multithreaded GEMM3M

Cleanup IOS build and disable FORTRAN on 32bit and ios builds for now

Revert "Cleanup Travis IOS xbuild and disable FORTRAN on 32bit and ios builds for now"

Travis recently appears unable to find a matching homebrew package for 32bit gfortran,
and the IOS crossbuild suffered from excessive output due to the known problem with "ASMNAME redefined"
warnings when CFLAGS is set in the environment

Cleanup Travis IOS xbuild and disable FORTRAN on 32bit and ios builds for now

Travis recently appears unable to find a matching homebrew package for 32bit gfortran,
and the IOS crossbuild suffered from excessive output due to the known problem with "ASMNAME redefined"
warnings when CFLAGS is set in the environment

We were corrupting r2 because the local entry wasn't being
setup correctly.

from #2322

by adding barriers (and a mutex lock for the non-OpenMP case) like it was already done for GEMM in level3_thread.c some time ago

zarch: treat z15 as z14 instead of generic

Change bad usage of "asum" to "sum" in ZARCH versions of ?sum

The ZARCH implementations of ?sum contain a cut & paste-error: An inline
assembly argument is named "sum", but the assembly references "asum"
instead.  The mismatch causes a build error.  This is fixed.

Signed-off-by: Dan Horák <dan@danny.cz>

revised fix windows compatible for #2313