allow to preset custom CFLAGS and LDFLAGS

Sometimes I need to add some flags (like -static for the linker), so
allow this for all CFLAGS and LDFLAGS used in this project.

Signed-off-by: Wolfram Sang <wsa@kernel.org>
Acked-by: Jean Delvare <jdelvare@suse.de>

CHANGES

@@ -2,6 +2,7 @@ i2c-tools CHANGES
 -----------------
 
 master
+  Makefile: allow to preset all CFLAGS and LDFLAGS variables
   tools: Consistently use snprintf instead of sprintf
          Restrict addresses 0x03-0x07, too (defined by I2C standard)
   decode-dimms: Print SPD revision for DDR3 too

eeprog/Module.mk

@@ -7,11 +7,11 @@
 
 EEPROG_DIR	:= eeprog
 
-EEPROG_CFLAGS	:= -Iinclude
+EEPROG_CFLAGS	+= -Iinclude
 ifeq ($(USE_STATIC_LIB),1)
-EEPROG_LDFLAGS	:= $(LIB_DIR)/$(LIB_STLIBNAME)
+EEPROG_LDFLAGS	+= $(LIB_DIR)/$(LIB_STLIBNAME)
 else
-EEPROG_LDFLAGS	:= -L$(LIB_DIR) -li2c
+EEPROG_LDFLAGS	+= -L$(LIB_DIR) -li2c
 endif
 
 EEPROG_TARGETS	:= eeprog

lib/Module.mk

@@ -9,7 +9,7 @@
 
 LIB_DIR		:= lib
 
-LIB_CFLAGS	:= -Wstrict-prototypes -Wshadow -Wpointer-arith -Wcast-qual \
+LIB_CFLAGS	+= -Wstrict-prototypes -Wshadow -Wpointer-arith -Wcast-qual \
 		   -Wcast-align -Wwrite-strings -Wnested-externs -Winline \
 		   -W -Wundef -Wmissing-prototypes -Iinclude
 

tools/Module.mk

@@ -9,13 +9,13 @@
 
 TOOLS_DIR	:= tools
 
-TOOLS_CFLAGS	:= -Wstrict-prototypes -Wshadow -Wpointer-arith -Wcast-qual \
+TOOLS_CFLAGS	+= -Wstrict-prototypes -Wshadow -Wpointer-arith -Wcast-qual \
 		   -Wcast-align -Wwrite-strings -Wnested-externs -Winline \
 		   -W -Wundef -Wmissing-prototypes -Iinclude
 ifeq ($(USE_STATIC_LIB),1)
-TOOLS_LDFLAGS	:= $(LIB_DIR)/$(LIB_STLIBNAME)
+TOOLS_LDFLAGS	+= $(LIB_DIR)/$(LIB_STLIBNAME)
 else
-TOOLS_LDFLAGS	:= -L$(LIB_DIR) -li2c
+TOOLS_LDFLAGS	+= -L$(LIB_DIR) -li2c
 endif
 
 TOOLS_TARGETS	:= i2cdetect i2cdump i2cset i2cget i2ctransfer