The asm code cannot currently be used with tcc since tcc doesn't support 't'
constraint.
Use inline C implementation instead, place it win32/include/tcc/tcc_libm.h, and
include it from win32/include/math.h.
Since fpclassify now works, it also fixes few other macros which depend on it.
Implicitly fixed: isfinite, isinf, isnan, isnormal.
The implementations were taken from musl-libc rs-1.0 (MIT license).
musl-libc: http://git.musl-libc.org/cgit/musl/tree/src/math?h=rs-1.0
license: http://git.musl-libc.org/cgit/musl/tree/COPYRIGHT?h=rs-1.0
