C math

• Adds function mangler to C target and OpenCL target so as to generate correct maths function according to the argument types.
• Examples:
• fmax for double, fmaxf for float on C target
• fmax for double and float on OpenCL target (there is no fmaxf in OpenCL standard)
• max for integer types on OpenCL target (there is no max for integer types in C)

Reference:

• C99 standard 7.12
• OpenCL maths functions