Updated `.travis.yml` file to add emulated tests for `ARMV6` and `ARMV8`
architectures with `gcc` and `clang`.  Created prebuilt images with
required dependencies. Squashed layers into one.

[Arm64) Revert A53 detection as A57

disable threading in C/ZSWAP copying from S/DSWAP

Add gfortran -frecursive option from upstream and #1847

Add minimum threshold for number of buffers

This patch reverts the decision of treating A53 like A57, which was
based on an analysis done on server class hardware and is not
representative of all A53s out there.

Fixes #1855.

gemm/dgemm: add a way for an arch kernel to specify preferred sizes

Restore Android/ARMv7 build fix from #778

Use installbsd on AIX

for #1811

(and fix misplaced parenthesis from previous commit). See #1803

Accomodate AIX install, which has different syntax

The current gemm threading code can make very unfortunate choices, for
example on my 10 core system a 1024x1024x1024 matrix multiply ends up
chunking into blocks of 102... which is not a vector friendly size
and performance ends up horrible.

this patch adds a helper define where an architecture can specify
a preference for size multiples.
This is different from existing defines that are minimum sizes and such.

The performance increase with this patch for the 1024x1024x1024 sgemm
is 2.3x (!!)

in the threading code there are cases where N or M can become 0,
and the optimized beta code did not handle this well, leading
to a crash

during the audit for the crash a few edge conditions on the if statements
were found and fixed as well

for #1803

Add get_num_procs implementation for AIX

(and copy HAIKU implementation to the non-TLS version of the code as well)

Ensure that blas_thread_init has been called in openblas_set_num_threads

Fix detection of Ryzen2 (missing CORE_ZEN)

Add DYNAMIC_ARCH support for ARM64

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.

Remove the runtime setting of P, Q, R parameters for
targets ARMV8, THUNDERX2T99. Instead set them as constants
in param.h at compile time.

Remove XGENE1 target as the implementation for the
same is incomplete. Moreover whoever wishes to use
on XGENE1 can use the generic ARMV8 target as there
are no XGENE1 specific optimizations in OpenBLAS.

Delay _hemv threading in attempt to address #1820

Use ThunderX2 Neon Kernels for ARMV8 Target

Currently the generic ARMV8 target uses C implementations
for many routines. Replace these with the neon implementations
written for THUNDERX2T99 target which are upto 6x faster for
certain routines.

enable the SGEMM/SKX C based kernel

In QA the final bug was found so now the sklyakex sgemm C based kernel can
be activated....

Use KERNEL_DEFINITIONS rather than COMMON_OPTS to pass -march=skylake…

Add -march=skylake-avx512 to CFLAGS when the target is Skylake