for #1851

fixes #1872

otherwise the introduction of a static array in 8e5a108 to improve #532 breaks concurrent calls from multiple threads as seen in #1844

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 (!!)

Add get_num_procs implementation for AIX

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

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.

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.

to aid in debugging cases like #1767

for #1766

Workaround for #1761 as that exposed a problem in the new code (which was intended to speed up multithreaded code only anyway).

Fix #1705 where we incorrectly calculate page locations.

Since we now use an allocation size that isn't a multiple of PAGESIZE, finding
the pages for run_bench wasn't terminating properly.  Now we detect if we've
found enough pages for the allocation and terminate the loop.

Unset memory table entry, not just the local pointer to it on shutdown

to fix crash with multiple instances of OpenBLAS, #1692

Temporarily disable special handling of OPENMP thread memory allocation

for issue #1673

Fix wrong redefinitions of snprintf for older MSVC

MS _snprintf_s takes an additional argument for the size of the buffer, so is not a direct replacement (utest/ctest.h from which I copied was wrong)

Define snprintf for older versions of MSVC

for #1677

Revert "Rewrite &= -> = and simplify the initial blocking phase."

Add cpuid for AMD Ryzen 2

Double MAX_ALLOCATING_THREADS to fix segfaults with Go and Octave

for #1641

fixes 1659

Fix apparent off-by-one error in calculation of MAX_ALLOCATING_THREADS

fixes #1641

merge develop

- Compiler TLS is now used only used when the compiler supports it
- If compiler TLS is unsupported, we use platform-specific TLS
- Only one variable (an index) is now in TLS
- We only access TLS once per alloc, and never when freeing
- Allocation / release info is now stored within the allocation itself, by
  over-allocating; this saves having external structures do the bookkeeping, and
  reduces some of the redundant data that was being stored (such as addresses)
- We never hit the alloc lock when not using SMP or when using OpenMP (that was
  my fault)
- Now that there are fewer tracking structures I think this is a bit easier to
  read than before

Initialize only the required subset of the jobs array, fix barriers and improve switch ratio on SkylakeX and Haswell. For issue #1622

* Support  upcoming Cannon Lake as Skylake X

a few places in the gemm scheduler code were missing barriers;
the code likely worked OK due to heavy use of volatile / _Atomic
but there's no reason to get this incorrect