Makefile: refactor include path settings

This commit merges commonly-used header include paths
to UBOOTINCLUDE and NOSTDINC_FLAGS variables, which are placed
at the top Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

Makefile

@@ -226,6 +226,15 @@ CHECK		= sparse
 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 		  -Wbitwise -Wno-return-void -D__CHECK_ENDIAN__ $(CF)
 
+# Use UBOOTINCLUDE when you must reference the include/ directory.
+# Needed to be compatible with the O= option
+UBOOTINCLUDE    :=
+ifneq ($(OBJTREE),$(SRCTREE))
+UBOOTINCLUDE	+= -I$(OBJTREE)/include
+endif
+UBOOTINCLUDE	+= -I$(srctree)/include \
+		-I$(srctree)/arch/$(ARCH)/include
+
 KBUILD_CPPFLAGS := -D__KERNEL__
 
 KBUILD_CFLAGS   := -Wall -Wstrict-prototypes \
@@ -238,7 +247,7 @@ export CPP AR NM LDR STRIP OBJCOPY OBJDUMP
 export MAKE AWK
 export DTC CHECK CHECKFLAGS
 
-export KBUILD_CPPFLAGS
+export KBUILD_CPPFLAGS NOSTDINC_FLAGS UBOOTINCLUDE
 export KBUILD_CFLAGS KBUILD_AFLAGS
 
 KBUILD_CFLAGS += -Os #-fomit-frame-pointer
@@ -254,6 +263,9 @@ KBUILD_CFLAGS	+= -g
 # option to the assembler.
 KBUILD_AFLAGS	+= -g
 
+NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
+CHECKFLAGS     += $(NOSTDINC_FLAGS)
+
 # Report stack usage if supported
 KBUILD_CFLAGS += $(call cc-option,-fstack-usage)
 

config.mk

@@ -94,8 +94,6 @@ RELFLAGS= $(PLATFORM_RELFLAGS)
 
 OBJCFLAGS += --gap-fill=0xff
 
-gccincdir := $(shell $(CC) -print-file-name=include)
-
 CPPFLAGS = $(KBUILD_CPPFLAGS) $(RELFLAGS)
 
 # Enable garbage collection of un-used sections for SPL
@@ -123,13 +121,8 @@ Please undefined CONFIG_SYS_GENERIC_BOARD in your board config file)
 endif
 endif
 
-ifneq ($(OBJTREE),$(SRCTREE))
-CPPFLAGS += -I$(OBJTREE)/include
-endif
-
-CPPFLAGS += -I$(TOPDIR)/include -I$(SRCTREE)/arch/$(ARCH)/include
-CPPFLAGS += -nostdinc	\
-	-isystem $(gccincdir) -pipe $(PLATFORM_CPPFLAGS)
+CPPFLAGS += $(UBOOTINCLUDE)
+CPPFLAGS += $(NOSTDINC_FLAGS) -pipe $(PLATFORM_CPPFLAGS)
 
 CFLAGS := $(KBUILD_CFLAGS) $(CPPFLAGS)
 

tools/Makefile

@@ -175,11 +175,9 @@ HOSTSRCS += $(addprefix $(SRCTREE)/lib/libfdt/,$(LIBFDT_OBJ_FILES-y:.o=.c))
 # Define _GNU_SOURCE to obtain the getline prototype from stdio.h
 #
 HOST_EXTRACFLAGS += -include $(SRCTREE)/include/libfdt_env.h \
-		-idirafter $(SRCTREE)/include \
-		-idirafter $(SRCTREE)/arch/$(ARCH)/include \
-		-idirafter $(OBJTREE)/include \
-		-I $(SRCTREE)/lib/libfdt \
-		-I $(SRCTREE)/tools \
+		$(patsubst -I%,-idirafter%, $(UBOOTINCLUDE)) \
+		-I$(SRCTREE)/lib/libfdt \
+		-I$(SRCTREE)/tools \
 		-DCONFIG_SYS_TEXT_BASE=$(CONFIG_SYS_TEXT_BASE) \
 		-DUSE_HOSTCC \
 		-D__KERNEL_STRICT_NAMES \

tools/env/Makefile

@@ -6,9 +6,7 @@
 #
 
 # Compile for a hosted environment on the target
-HOST_EXTRACFLAGS  = -idirafter $(SRCTREE)/include \
-		-idirafter $(SRCTREE)/arch/$(ARCH)/include \
-		-idirafter $(OBJTREE)/include \
+HOST_EXTRACFLAGS  = $(patsubst -I%,-idirafter%, $(UBOOTINCLUDE)) \
 		-idirafter $(SRCTREE)/tools/env \
 		-DUSE_HOSTCC \
 		-DTEXT_BASE=$(TEXT_BASE)