Don't use libm with libtiff due to conflict with libmsvcrt
Exclude libm from MINGW since math related functions are already included in libmsvcrt.a. https://stackoverflow.com/questions/48134247/why-i-dont-need-the-flag-lm-in-mingw-but-in-linux-i-need-that-explicitly
Including libm creates a conflict with definitions of log10 in both libm and libmsvcrt