Add Intel Goldmont Plus CPUID

fixes #2227

Make getarch compile with PGI

rebase

* Add multithreading support

copied from the ThunderX2T99 kernel. For #2221

Make the new DGEMM regression test properly depend on CBLAS and LAPACKE

fixes #2215

Remove case-sensitivity in x86 LSAME on (AMD) cpus without CMOV

Problem was already noticed some years ago in #238, but back then the problem was only corrected in one of the #ifdef branches.
Fixes #2214

Avoid spurious dependency on the fortran runtime despite NOFORTRAN=1

for cases where a fortran compiler is present but not wanted (e.g. not fully functional)

Silence two nuisance warnings from gcc

Provide more information on mmap/munmap failure

Replace vpermpd with vpermilpd in the Haswell DTRMM kernel

Replace most vpermpd calls in the Haswell DTRSM_RN kernel

for #2207

Update CPUID recognition for Intel Ice Lake

to improve performance on AMD Zen (#2180) applying wjc404's improvement of the DGEMM kernel from #2186

Add vbroadcastsd kernel to dgemm_kernel_4x8_haswell.S

Makefile.arm: remove -march flags

Override special make variables

as seen in https://github.com/xianyi/OpenBLAS/issues/1912#issuecomment-514183900 , any external setting of TARGET_ARCH (which could result from building OpenBLAS as part of a larger project that actually uses this variable) would cause the utest build to fail. 
(Other subtargets appear to be unaffected as they do not use implicit make rules)

MAINT: remove legacy CMake endif()

Replace vpermpd with vpermilpd in the Haswell/Zen zdot microkernel

Update dgemm_kernel_4x8_haswell.S for reducing cache misses

* clean up a case where CMake endif()
contained the conditional used in the
if(), which is no longer needed /
discouraged since our minimum required
CMake version supports the modern syntax

to improve performance on Zen/Zen2 (as demonstrated by wjc404 in #2180)

Update "dgemm_kernel_4x8_haswell.S" for improving performance on zen2 chips