libc: Import from TF-A

Based on arm-trusted-firware commit 873e394b3bf93214a441f9f98237b58fbbea55aa

Change-Id: I510e092f2b9ff333e9461bdde8d80ed1fab1460c
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
diff --git a/lib/libc/libc.mk b/lib/libc/libc.mk
new file mode 100644
index 0000000..e1b5560
--- /dev/null
+++ b/lib/libc/libc.mk
@@ -0,0 +1,34 @@
+#
+# Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+LIBC_SRCS	:=	$(addprefix lib/libc/,		\
+			abort.c				\
+			assert.c			\
+			exit.c				\
+			memchr.c			\
+			memcmp.c			\
+			memcpy.c			\
+			memmove.c			\
+			memset.c			\
+			printf.c			\
+			putchar.c			\
+			puts.c				\
+			snprintf.c			\
+			strchr.c			\
+			strcmp.c			\
+			strlcpy.c			\
+			strlen.c			\
+			strncmp.c			\
+			strnlen.c			\
+			strrchr.c)
+
+ifeq (${ARCH},aarch64)
+LIBC_SRCS	+=	$(addprefix lib/libc/aarch64/,	\
+			setjmp.S)
+endif
+
+INCLUDES	+=	-Iinclude/lib/libc		\
+			-Iinclude/lib/libc/$(ARCH)	\