Make NO_AVX512 option override the AVX512 compile test in CMAKE builds as well

The need to call it .tmp existed only when it was generated by a tmpfile call, and the "-x c" option to tell the compiler it is actually a C source is not universally supported (this broke the test with clang-cl at least)

* Fix compiler identification and option setting

* Handle BINARY=32 option on X86_64

* Add xGEMM3M unroll parameters for crossbuild-target CORE2

* Replace bogus mingw64/32bit CI job with actual 32bit build

mingw64 is not multilib-capable, so using an x86_64-mingw with BINARY=32 in the CI was not going to work anyway (but build passed while BINARY=32 was ignored).

* clean up a case where CMake endif()
contained the conditional used in the
if(), which is no longer needed /
discouraged since our minimum required
CMake version supports the modern syntax

for #2056, using same approach as #2058

* Handle Android environments that identify as Linux

termux terminal emulator does this, causing build failures through missed defines in common.h

Add -march=skylake-avx512 when required

fixes #1797