Ofast enables possibly unsafe optimizations in addition to O3. This
appears to have been added and then just continually copied into later
Power architectures, and it wasn't included in the CMake build system
when that was introduced.

Replace this with O3 so that the same level of optimization is done by
the compiler.

Recent commit d99aad8ee3 added
extra `)`. This patch fixes the warning from Makefile.

This patch fixes errors when using Open XL C compiler on AIX.
Tested with gcc/xlf and ibm-clang/xlf compiler combinations.

This patch fixes errors when using xlf as fortran compiler on Linux.
Tested with gcc/xlf and clang/xlf compiler combinations.

Fixing syntax issue in Makefile.power added by recent commit
af19cda65a

* Add correct "recursive" option for xlf (from reference-lapack issue 606)

Adding check for compiler type before checking GCC version in Makefile.
This allows clang to use power9 instead of power8 when CORE is POWER9.

As gcc defaults to -malign-power, removing that option. Also
adding -fno-integrated-as to use GNU assembler for powerpc
assembly optimization files. Fixed other compilation errors
reported in dgemv_t.c file.

[WIP] fix compilation on AIX

As compiler enabled mcpu option as power10, changing it from future.

This is the initial patch to support build infrastructure
for POWER10 architecture.

for #2154 (see gcc bug 90329)

IBM MASS library is upgraded to 8.1.5 and 8.1.3 is not available.
Update README.md and Makefile.power to use version 8.1.5 of libxlmass.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>