Couple of build issues on 32bit MSVC v143 build with /arch:SSE

[Epixu]

Hi again, I'm experiencing build errors with the current master (e651ec360f22d5f9d7fb2c75c5025db614f78b8c) Many issues have been fixed regarding my prior issue, including many of the failing tests involving precision discrepancies. Here's the summary:

All my issues apply to MSVC v143 x86 builds - I have 5 such builds, each with a different /arch:XXX option:

1. The two build issues apply only to MSVC v143 x86 with /arch:SSE enabled

a) The first build issue involves reaching line 4774 here: https://github.com/simd-everywhere/simde/blob/e651ec360f22d5f9d7fb2c75c5025db614f78b8c/simde/x86/sse2.h#L4770-L4774

The line involves GCC syntax, it should be guarded. I can fix this build issue by doing:

simde_mm_pause (void) {
  #if defined(SIMDE_X86_SSE2_NATIVE)
    _mm_pause();
  #elif defined(SIMDE_ARCH_X86)
    #if defined(_MSC_VER)
      _mm_pause();
    #else
      __asm__ __volatile__("pause");
    #endif
  #elif defined(SIMDE_ARCH_ARM_NEON)

But not sure if _mm_pause() won't cause invalid instruction at runtime, if the SIMDE_X86_SSE2_NATIVE isn't available. Is it available on SIMDE_X86_SSE_NATIVE?

b) The second build issue involves SVML

I can circumvent it by simply guard the include of the svml.h - not sure if that is intended though. There should be fallback alternatives in SIMDe? These errors seemingly involve only 'simde__m128d' to '__m128d' conversion issues.

2. The test issues apply to all /arch options on MSVC v143 x86 builds:

They seemingly affect only pow functions precision, but my tests aren't exhaustive, so not sure.