Big MSL_C update (#546)

* match acos, asin, fmod, and math_ppc

* match many files in MSL_C
math_ppc, s_copysign, s_cos, s_modf, s_sin, s_tan, w_acos, w_asin, w_fmod, w_pow

include/PowerPC_EABI_Support/Msl/MSL_C/MSL_Common/math_ppc.h

@@ -0,0 +1,5 @@
+double acos(double x);
+double tan(double);
+double sin(double);
+double cos(double);
+double atan2(double);