Added __frem to CRT (wraps fmodf)

[ZERICO2005]

float fwrap(float x, float min, float max) {
    if (min > max)
        return fwrap(x, max, min);
    return (x >= 0 ? min : max) + fmodf(x, max - min);
}

This code when compiled with -Ofast (in C) would emit a lib-call to __frem instead of a call _fmodf. However, __frem wasn't defined in the toolchain. This has been fixed by adding the CRT routine for __frem, which wraps _fmodf for now.

Credit to @merthsoft for finding this bug

[adriweb]

(retval fixed by 82f472c)