* 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
Martin Kroeker