[Tinycc-devel] Some missing math functions for WIN32/64.

[Tyge Løvset]

I added tgamma(), lgamma(), cbrt(), log2(), exp2() C99 math functions to win32/tcc_libm.h

 

I hope/think I managed to implement the gamma funcs as compact/fast/accurate as practical possible, while adhering to the formal specs regarding error handling. tgamma() and lgamma() are mutually dependent to handle the full input output value ranges.

 

win32/include/math.h is quite messy and could be simplified, but I left it unchanged. There are still a few rarely used math functions missing on windows, but can be added later. 

 

You can compare output vs. built-in functions on other platforms/compilers with the test I left in the commit comment.