Implement missing trigonometric functions
The trigonometric functions sine and cosine are currently implemented properly only for ia32 and amd64. Therefore code relying on these functions (e.g. GUI rendering) does not work correctly on other platforms.
A generic software implementation of these transcendetal functions with a reasonable precision should be available for platforms without a FPU or where the FPU is unable to calculate these functions directly. Platforms which support such functions in hardware should preferably use the hardware implementation.