90% MKL 1-thread performance.

Rewrite ARMV8 code to allow cross-compilation for IOS

... which does not perform the automatic numbering on instantiation that the _@ suffix signifies

fixed bug power9 strmm . BLAS-TESTER passes

* 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

* Revert #2051 and add a better fix for TARGET=generic with DYNAMIC_ARCH
fixes #2257 without breaking #2048 again

possible cgemv,caxpy,cdot fix

broken by #2222 as CREAL,CIMAG do not expand to a valid lvalue with these compilers

* Add multithreading support

copied from the ThunderX2T99 kernel. For #2221

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

Replace vpermpd with vpermilpd in the Haswell DTRMM kernel

Replace most vpermpd calls in the Haswell DTRSM_RN kernel

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

Replace vpermpd with vpermilpd in the Haswell/Zen zdot microkernel

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

replaced a bunch of vpermpd instructions with vpermilpd and vperm2f128