undef functions needed for usage within libc

libc/string/powerpc/memcpy.c

@@ -21,6 +21,7 @@
 
 #include <string.h>
 
+#undef memcpy
 void attribute_hidden *__memcpy(void *to, const void *from, size_t n)
 /* PPC can do pre increment and load/store, but not post increment and load/store.
    Therefore use *++ptr instead of *ptr++. */

libc/string/powerpc/memmove.c

@@ -21,6 +21,7 @@
 
 #include <string.h>
 
+#undef memmove
 void attribute_hidden *__memmove(void *to, const void *from, size_t n)
 {
 	unsigned long rem, chunks, tmp1, tmp2;

libc/string/powerpc/memset.c

@@ -31,6 +31,8 @@ static inline int expand_byte_word(int c){
 	    : "=r" (c) : "0" (c));
 	return c;
 }
+
+#undef memset
 void attribute_hidden *__memset(void *to, int c, size_t n)
 {
 	unsigned long rem, chunks;