Setting DYNAMIC_ARCH=1 on POWER9 does not build POWER9 files due to some
compiler version checks.  This patch fixes some of the macros that are used
to check compiler version.  On fixing those checks, there are some new make
failures related to icamin, icamax, isamin, isamax and caxpy files on POWER9.
This patch fixes those failures as well.

The implementation is a hybird of the ARMV8 one with some of the
improved TX2 rountines along with specifying -march=v8.2-a

[WIP] Add support for Ampere EMAG8180 ARMV8 cpu

add in runtime cpu detection for zarch

* 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

Auto-add "-fno-second-underscore" option to make LAPACKE compile (as it calls LAPACK functions that may have gotten a second underscore added otherwise). Also support -R for rpath when parsing compiler directives in f_check

* Add gcc7-generated assembly files for POWER8/9 isa/ica-min/max and POWER9 caxpy

To work around internal compiler errors encountered when compiling the original C source with gcc 4 and 5, and wrong code generated by gcc 8.3.0

* Use gcc-generated assembly instead of original C sources

to work around internal compiler errors encountered with gcc 4.8/5.4 and wrong code generation by gcc 8.3

* Use gcc-generated assembly instead of the original C source

to work around internal compiler errors encountered with gcc 4.8 and 5.4, and wrong code generation by gcc 8.3

* Add gcc7-generated assembler version of caxpy for power8

to work around wrong code generated by gcc 8.3

* Handle CONJ define for caxpyc

* Handle CONJ define for caxpyc

* Add gcc7-generated assembly cdot for POWER9

* Use prebuilt assembly for POWER9 cdot

created with gcc 7.3.1 to work around ICE in older gcc versions

* Exclude POWER9 from DYNAMIC_ARCH when gcc versions is lower than 6

* Update Makefile.system

* Use PROLOGUE macro to ensure correct function name for DYNAMIC_ARCH

* Disable POWER9 with old gcc versions

for #2237

Setting it with a simple "uname -m" just to be able to decide whether to compile getarch.c with -march=native
may actually keep getarch from doing a proper probe. Fixes #2231, a regression caused by #2110

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)

Fixes for PGI compiler

fixes #2149

Add gfortran workaround for C->FORTRAN ABI violation

for #2154 (see gcc bug 90329)

21eda8b5 introduced a check in getarch.c to test if the compiler is capable of
AVX512. This check currently fails, since the used __AVX2__ macro is only
defined if getarch itself was compiled with AVX2/AVX512 support. Make sure this
is the case by building getarch with -march=native on x86_64. It is only
supposed to run on the build host anyway.

for calling from concurrent threads

for #2033

fixes #2033

fixes #1961

the build will now abort with an error message when an undefined build TARGET is named

Fixes #1938

override user-provided FFLAGS if necessary

FreeBSD uses powerpc64 name for POWER architecture. Use correct Makefile for this platform.

Set LIBSONAME suffix to .a for AIX

another fix for #1803

Enable DYNAMIC_ARCH feature on ARM64. This patch uses the cpuid
feature in linux kernel to detect the core type at runtime
(https://www.kernel.org/doc/Documentation/arm64/cpu-feature-registers.txt).

If this feature is missing in kernel, then the user should use the
OPENBLAS_CORETYPE env variable to select the desired core type.

Handle conflicting usage of ARCH in at least some BSD environments

fixes #1796