Import gx, PadClamp, rest of mtx, TRK 2.6 and MSL (#525)

* Match mtx and Padclamp.c

* Match the rest of GX

* Import TRK 2.6

* Import MSL headers and files

* Merge some MSL headers into ours

src/MSL_C.PPCEABI.bare.H/float.c

@@ -0,0 +1,5 @@
+#include "PowerPC_EABI_Support/Msl/MSL_C/MSL_Common/float.h"
+
+unsigned long __float_nan[] = { 0x7FFFFFFF };
+
+unsigned long __float_huge[] = { 0x7F800000 };