libc: Integrate strrchr in libc

Change-Id: I3ddc07cb02d73cd7614af7a5b21827aae155f9a0
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/lib/libc/libc.mk b/lib/libc/libc.mk
index 554f36b..daa2ec1 100644
--- a/lib/libc/libc.mk
+++ b/lib/libc/libc.mk
@@ -21,7 +21,8 @@
 			strcmp.c			\
 			strlen.c			\
 			strncmp.c			\
-			strnlen.c)
+			strnlen.c			\
+			strrchr.c)
 
 INCLUDES	+=	-Iinclude/lib/libc		\
 			-Iinclude/lib/libc/$(ARCH)	\