msvc9 compatibility 

This commit should *NOT* be merged as is (the extra source files should be required on windows only). It's just a hack I did on win64 with msvc9 to build scipy on win64 and I thought that perhaps it would help making a true solution that works across platforms and compilers.

I believe there must be a more elegant way to solve this (for instance, to use a single helper library, instead of copying the same code in multiple folders)

Also, before using the code, it would be a good idea to double-check the math.

Also note that in msvc2013 some of the functions (i.e. the math functions in C99) are included by the compiler and native runtime library, so defining them is not required any more