kbuild: Use Kbuild.include

This commit adjusts some files to use Kbuild.include.

 - Use cc-option defined in Kbuild.include
    (Delete cc-option in config.mk)
 - Use cc-version defined in
    (Delete cc-version in config.mk)
 - Move binutils-version and dtc-version to Kbuild.include
     by analogy to cc-version

This commit also adds srctree (same as SRCTREE)
to use Kbuild scripts.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/Makefile b/Makefile
index 0c1eef3..e4045bc 100644
--- a/Makefile
+++ b/Makefile
@@ -102,9 +102,10 @@
 SPLTREE		:= $(OBJTREE)/spl
 TPLTREE		:= $(OBJTREE)/tpl
 SRCTREE		:= $(CURDIR)
+srctree		:= $(SRCTREE)
 TOPDIR		:= $(SRCTREE)
 LNDIR		:= $(OBJTREE)
-export	TOPDIR SRCTREE OBJTREE SPLTREE TPLTREE
+export	TOPDIR SRCTREE srctree OBJTREE SPLTREE TPLTREE
 
 MKCONFIG	:= $(SRCTREE)/mkconfig
 export MKCONFIG
@@ -126,8 +127,6 @@
 
 #########################################################################
 
-build := -f $(TOPDIR)/scripts/Makefile.build -C
-
 # The "tools" are needed early, so put this first
 # Don't include stuff already done in $(LIBS)
 # The "examples" conditionally depend on U-Boot (say, when USE_PRIVATE_LIBGCC
@@ -198,6 +197,10 @@
 HOSTLDFLAGS += $(call os_x_before, 10, 5, "-multiply_defined suppress")
 endif
 
+# We need some generic definitions (do not try to remake the file).
+$(srctree)/scripts/Kbuild.include: ;
+include $(srctree)/scripts/Kbuild.include
+
 # Make variables (CC, etc...)
 
 AS		= $(CROSS_COMPILE)as
diff --git a/config.mk b/config.mk
index dfe81fa..ba42641 100644
--- a/config.mk
+++ b/config.mk
@@ -48,35 +48,6 @@
 PLATFORM_LDFLAGS =
 
 #########################################################################
-#
-# Option checker, gcc version (courtesy linux kernel) to ensure
-# only supported compiler options are used
-#
-CC_OPTIONS_CACHE_FILE := $(OBJTREE)/include/generated/cc_options.mk
-CC_TEST_OFILE := $(OBJTREE)/include/generated/cc_test_file.o
-
--include $(CC_OPTIONS_CACHE_FILE)
-
-cc-option-sys = $(shell mkdir -p $(dir $(CC_TEST_OFILE)); \
-		if $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o $(CC_TEST_OFILE) \
-		> /dev/null 2>&1; then \
-		echo 'CC_OPTIONS += $(strip $1)' >> $(CC_OPTIONS_CACHE_FILE); \
-		echo "$(1)"; fi)
-
-ifeq ($(CONFIG_CC_OPT_CACHE_DISABLE),y)
-cc-option = $(strip $(if $(call cc-option-sys,$1),$1,$2))
-else
-cc-option = $(strip $(if $(findstring $1,$(CC_OPTIONS)),$1,\
-		$(if $(call cc-option-sys,$1),$1,$2)))
-endif
-
-# cc-version
-# Usage gcc-ver := $(call cc-version)
-cc-version = $(shell $(CONFIG_SHELL) $(SRCTREE)/scripts/gcc-version.sh $(CC))
-binutils-version = $(shell $(CONFIG_SHELL) $(SRCTREE)/scripts/binutils-version.sh $(AS))
-dtc-version = $(shell $(CONFIG_SHELL) $(SRCTREE)/scripts/dtc-version.sh $(DTC))
-
-#########################################################################
 
 # Load generated board configuration
 ifeq ($(CONFIG_TPL_BUILD),y)
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 547e15d..ca5fd56 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -140,6 +140,10 @@
 # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
 cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
 
+# added for U-Boot
+binutils-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/binutils-version.sh $(AS))
+dtc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/dtc-version.sh $(DTC))
+
 # cc-ldoption
 # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
 cc-ldoption = $(call try-run,\
@@ -161,7 +165,9 @@
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 # Usage:
 # $(Q)$(MAKE) $(build)=dir
-build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
+#build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
+# temporary
+build := -f $(srctree)/scripts/Makefile.build -C
 
 ###
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 1b3d77f..7789efa 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -2,6 +2,7 @@
 .PHONY: all
 all:
 
+include $(srctree)/scripts/Kbuild.include
 include $(TOPDIR)/config.mk
 
 # variable LIB is used in examples/standalone/Makefile
diff --git a/spl/Makefile b/spl/Makefile
index 5339338..f273015 100644
--- a/spl/Makefile
+++ b/spl/Makefile
@@ -14,6 +14,8 @@
 # Based on top-level Makefile.
 #
 
+include $(srctree)/scripts/Kbuild.include
+
 CONFIG_SPL_BUILD := y
 export CONFIG_SPL_BUILD
 
@@ -127,8 +129,6 @@
 $(error could not find linker script)
 endif
 
-build := -f $(TOPDIR)/scripts/Makefile.build -C
-
 # Special flags for CPP when processing the linker script.
 # Pass the version down so we can handle backwards compatibility
 # on the fly.