Enable passing a triple to wamrc

[lum1n0us]

$ wamrc -v=5 --target=i686-xx-mingw-eabi  -o 1.aot ./1.wasm 

[12:18:41:781 - 7FD7911C6BC0]: triple: i686-xx-mingw-eabi => normalized: i686-xx-windows-gnu

Create AoT compiler with:
  target:        i686
  target cpu:    
  target triple: i686-xx-windows-gnu   <= NORMALIZED
  cpu features:  
  opt level:     3
  size level:    3
  output format: AoT file

[calvin2021y]

Thanks for this solution.

Is is possiable to add more option related to llvm from wamrc, some like -flto=thin, -flto=full, -O2 by wamrc to pass to llc.

Not sure this is reasonable