[PowerPC] force applications linked with lib CSU to have .got

Summary:
This forces applications linked with lib CSU to have a .got, fixing binaries
linked with LLD9 after secure-plt was enabled on FreeBSD.

Submitted by:	Alfredo Dal'Ava Junior (alfredo.junior_eldorado.org.br)
Differential Revision:	https://reviews.freebsd.org/D21476

lib/csu/powerpc/crt1.c

@@ -102,3 +102,9 @@ __asm__(".text");
 __asm__("eprol:");
 __asm__(".previous");
 #endif
+
+#ifndef PIC
+__asm__(".text\n"
+	"\t.global _GLOBAL_OFFSET_TABLE_\n"
+	"\t.reloc 0, R_PPC_NONE, _GLOBAL_OFFSET_TABLE_");
+#endif