Fixed bug 1820 - building SDL as a static library with static runtime doesn't compile/link with visual studio

norfanin

Adds a condition so only the MSVC 2012 compiler defines the macros for the functions of its version.

Attaching a patch that adds a condition so that the HAVE_X supported by MSVC 2012 only get defined with that compiler. MSVC 2008 and 2010 will then build without any modification to the SDL source code.

Also moved HAVE_M_PI to a separate check. The Microsoft headers require _USE_MATH_DEFINES to be defined before they define the constants.

--HG--
extra : rebase_source : 5a348adc971f36b3e524a3f30759c6b4c04c400d