Enhancements for SIMD advisor

[NingW101]

According to the emscripten documentation, there are five different ways to leverage WebAssembly SIMD in your C/C++ programs:

• Enable LLVM/Clang SIMD autovectorizer to automatically target WebAssembly SIMD, without requiring changes to C/C++ source code.
• Write SIMD code using the GCC/Clang SIMD Vector Extensions (__attribute__((vector_size(16))))
• Write SIMD code using the WebAssembly SIMD intrinsics (#include <wasm_simd128.h>)
• Compile existing SIMD code that uses the x86 SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2 or 128-bit subset of the AVX intrinsics (#include <*mmintrin.h>)
• Compile existing SIMD code that uses the ARM NEON intrinsics (#include <arm_neon.h>)

x86intrin.h header file is usually used in C\C++ codebase, which contains the support of multiple instruction sets, commonly covering the one or several of MMX, SEE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AVX2, etc, but it is related to the what compiler you use. For the clang inside of the emsdk, it contains ia32intrin.h & mmintrin.h, which will not handled by emscripten during the building, so the better ways to port your project with SIMD support are:

• if there is no SIMD code used in the codebase and you want to enable SIMD option to let compiler autovector to target wasm-simd, add -msimd128 is enough.
• if your current codebase exists SIMD code, include <wasm_simd128.h> and then use the wasm SIMD intrinsics to replace your current code.
• if your current codebase include SIMD code targeting x86 SSE* instruction sets, add -msimd128 and additionally corresponding flag.
  • For example, SSE: pass -msse and #include <xmmintrin.h>. Use #ifdef __SSE__ to gate code.

[NingW101]

Compile existing SIMD code that uses the x86 SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2 or 128-bit subset of the AVX intrinsics (#include <*mmintrin.h>)

if your current codebase include SIMD code targeting x86 SSE* instruction sets, add -msimd128 and additionally corresponding flag.
For example, SSE: pass -msse and #include <xmmintrin.h>. Use #ifdef __SSE__ to gate code.

Maybe we can scan if these SIMD intrinsics header files exist in the codebase, and add corresponding compiler flags when user enable SIMD option from UI.

[NingW101]

Enhancements finalized:

1. scan the codebase to check if following header files are included:

   SIMD set	Header file	Action
   SSE	#include <xmmintrin.h>	-msse
   SSE2	#include <emmintrin.h>	-msse2
   SSE3	#include <pmmintrin.h>	-msse3
   SSSE3	#include <tmmintrin.h>	-mssse3
   SSE4.1	#include <smmintrin.h>	-msse4.1
   SSE4.2	#include <nmmintrin.h>	-msse4.2
   AVX	#include <immintrin.h>	-mavx

   implement action to add corresponding -mxxx flag into the compiler flags.

2. scan the error content to match if it contains the x86intrin.h, prompt developers that the emscripten does not support this intrinsic header, consider to rewrite the code with the apis provided by wasm_simd128.h or just remove it if the codebase does not use the SIMD code. Tag the link of Using SIMD with emscripten