Remove sun musl fdlibm math library

The libm code from musl wasn't being used since most of these functions
are implemented using x87 which goes faster than a library intended for
risc machines.

libc/libc.mk

@@ -18,7 +18,6 @@ o/$(MODE)/libc:	o/$(MODE)/libc/alg		\
 		o/$(MODE)/libc/intrin		\
 		o/$(MODE)/libc/linux		\
 		o/$(MODE)/libc/log		\
-		o/$(MODE)/libc/math		\
 		o/$(MODE)/libc/mem		\
 		o/$(MODE)/libc/nexgen32e	\
 		o/$(MODE)/libc/nt		\