Expressly enable neon for use with intrinsics if available

Optimize saxpy for POWER10

This patch makes use of new POWER10 vector pair instructions for
loads and stores.

Move definitions that are neither needed nor supported on Solaris

Merge back 0.3.12 tag (and Changelog typo fixes) from release

Merge from develop for 0.3.12 release

Comment out  BUILD_SINGLE etc. in Makefile.rule and add a short explanation

Fix grouping of sladiv1/dladiv1/ilaenv2stage in gensymbol

rebase

Increase and unify BUFFERSIZE on POWER;fix gcc inline warning

Fix twisted spelling that broke the gfortran version test again

Fix compiler version check for -mavx2 support (DYNAMIC_ARCH case)

Fix macro used in argument conversion (LAPACK PR 458)

to fix overflow warning for PWR8 ZGEMM and PWR9 C/ZGEMM and avoid size mismatches in DYNAMIC_ARCH

rebase

Optimize scopy/ccopy for POWER10

actually check that version is greater than 4.7

This patch makes use of new POWER10 vector pair instructions for
loads and stores. Also reorganized all variants of copy functions
to make use of same kernel.

Fix build with -Werror=return-type

Enable -mavx2 for flang as well where supported

dgemm_tcopy_16_skylakex.c CNAME function should return an int, add a
return 0 similar to other files.

rebase

Add binutils version check as prerequisite for POWER10 in DYNAMIC_ARCH build

x86_64: clobber all xmm registers after vzeroupper