Support building with MinGW(-w64)

_From [VanBoxem...@gmail.com](https://code.google.com/u/108779539249446421349/) on December 15, 2011 14:45:07_

What version of DynamoRIO are you using? trunk ( r1149 ) What operating system version are you running on? Windows 7 x64 SP1 What steps will reproduce the problem? cmake ../../Source/dynamorio -G"MinGW Makefiles"

CMake error:
-- The C compiler identification is GNU
-- Check for working C compiler: M:/Development/mingw64/bin/gcc.exe
-- Check for working C compiler: M:/Development/mingw64/bin/gcc.exe -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- The CXX compiler identification is GNU
-- Check for working CXX compiler: M:/Development/mingw64/bin/g++.exe
-- Check for working CXX compiler: M:/Development/mingw64/bin/g++.exe -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Version number: 3.0.1194
CMake Error at CMakeLists.txt:479 (message):
assembler not found: required to build

-- Configuring incomplete, errors occurred!

I was under the impression CMake could detect the assembler by itself, it looks like you're manually doing all that. I could be wrong though.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=638_