Clang in base now supports -mlongcall, so remove this hack

PR:		215947
MFC after:	2 weeks

lib/csu/powerpc64/Makefile

@@ -9,16 +9,6 @@ CFLAGS+=	-I${.CURDIR:H}/common \
 		-I${SRCTOP}/lib/libc/include \
 		-mlongcall
 
-# XXX: See the log for r232932 as to why the above -mlongcall is needed.  Since
-# clang doesn't support -mlongcall, and testing shows a clang linked with a
-# clang-built csu segfaults, this must currently be compiled with gcc.  Once
-# clang supports -mlongcall, or we get a fixed ld, this can be revisited.
-.include <bsd.compiler.mk>
-.if ${COMPILER_TYPE} != "gcc"
-CC:=		gcc
-COMPILER_TYPE:=	gcc
-.endif
-
 FILES=		${OBJS}
 FILESMODE=	${LIBMODE}
 FILESOWN=	${LIBOWN}