Add make macros to build library archives

This patch adds all the make macros needed to create a library archive
and to use it in the link stage.

Change-Id: I26597bfd6543649d0b68a9b1e06aec1ba353e6de
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/Makefile b/Makefile
index 533cb8a..2609864 100644
--- a/Makefile
+++ b/Makefile
@@ -670,6 +670,8 @@
     CPPFLAGS		+= 	-Wno-error=deprecated-declarations -Wno-error=cpp
 endif
 
+$(eval $(call MAKE_LIB_DIR))
+
 # Expand build macros for the different images
 ifeq (${NEED_BL1},yes)
 $(eval $(call MAKE_BL,1))