Create common.make with LOCAL_CFLAGS and friends

Create a common.make for definitions that are shared between tests/Makefile
and programs/Makefile, to facilitate maintenance. Start populating it with
CFLAGS/LDFLAGS variables. More to follow in subsequent commits.

Keep library/Makefile independent, at least for the time being.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/Makefile b/programs/Makefile
index 9ee9820..b03e613 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -1,23 +1,10 @@
-
-# To compile on SunOS: add "-lsocket -lnsl" to LDFLAGS
-
-CFLAGS	?= -O2
-WARNING_CFLAGS ?= -Wall -Wextra -Wformat=2 -Wno-format-nonliteral
-WARNING_CXXFLAGS ?= -Wall -Wextra -Wformat=2 -Wno-format-nonliteral
-LDFLAGS ?=
-
 MBEDTLS_TEST_PATH = ../tests
 # Support code used by test programs and test builds, excluding TLS-specific
 # code which is in the src/test_helpers subdirectory.
 MBEDTLS_TEST_OBJS = $(patsubst %.c,%.o,$(wildcard ${MBEDTLS_TEST_PATH}/src/*.c ${MBEDTLS_TEST_PATH}/src/drivers/*.c))
 
 LOCAL_CFLAGS = $(WARNING_CFLAGS) -I$(MBEDTLS_TEST_PATH)/include -I../include -D_FILE_OFFSET_BITS=64
-LOCAL_CXXFLAGS = $(WARNING_CXXFLAGS) -I../include -I../tests/include -D_FILE_OFFSET_BITS=64
-LOCAL_LDFLAGS = ${MBEDTLS_TEST_OBJS} 		\
-		-L../library 			\
-		-lmbedtls$(SHARED_SUFFIX)	\
-		-lmbedx509$(SHARED_SUFFIX)	\
-		-lmbedcrypto$(SHARED_SUFFIX)
+include ../scripts/common.make
 
 ifeq ($(shell uname -s),Linux)
 DLOPEN_LDFLAGS ?= -ldl