add clang and upgrade mingw64

use this new mingw64
will save same place for extra runtime need

binary for test

cef_binary_3.2623.1401.gb90a3be_windows32
note
for complie on windows xp:

1. llvm<=3.7.*
2. go<=1.10.*
3. mingw tested on v6.0
4. cmake tested on 3.12.2
   extra
   cmake -G "MinGW Makefiles" . -DCMAKE_BUILD_TYPE=Release && mingw32-make