Move stdlib header files to include/lib/stdlib

* Move stdlib header files from include/stdlib to include/lib/stdlib for
  consistency with other library headers.
* Fix checkpatch paths to continue excluding stdlib files.
* Create stdlib.mk to define the stdlib source files and include directories.
* Include stdlib.mk from the top level Makefile.
* Update stdlib header path in the fip_create Makefile.
* Update porting-guide.md with the new paths.

Change-Id: Ia92c2dc572e9efb54a783e306b5ceb2ce24d27fa

lib/stdlib/stdlib.mk

+#
+# Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# Neither the name of ARM nor the names of its contributors may be used
+# to endorse or promote products derived from this software without specific
+# prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+
+STDLIB_SRCS	:=	$(addprefix lib/stdlib/,	\
+			abort.c				\
+			assert.c			\
+			exit.c				\
+			mem.c				\
+			printf.c			\
+			putchar.c			\
+			puts.c				\
+			sscanf.c			\
+			strchr.c			\
+			strcmp.c			\
+			strlen.c			\
+			strncmp.c			\
+			subr_prf.c)
+
+INCLUDES	+=	-Iinclude/lib/stdlib		\
+			-Iinclude/lib/stdlib/sys

tools/fip_create/Makefile

@@ -69,7 +69,7 @@ ${PROJECT}: ${OBJECTS} Makefile
 # path. This avoids conflicts with definitions in the compiler standard
 # include path.
 #
-uuid.h : ../../include/stdlib/sys/uuid.h
+uuid.h : ../../include/lib/stdlib/sys/uuid.h
 	$(call SHELL_COPY,$<,$@)
 
 firmware_image_package.h : ../../include/common/firmware_image_package.h