diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 55b35b4..a048ec7 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -1,22 +1,41 @@
 ####
 # kbuild: Generic definitions
 
-# Convinient variables
+# Convenient variables
 comma   := ,
 squote  := '
 empty   :=
 space   := $(empty) $(empty)
 
 ###
+# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
+dot-target = $(dir $@).$(notdir $@)
+
+###
 # The temporary file to save gcc -MD generated dependencies must not
 # contain a comma
-depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
+depfile = $(subst $(comma),_,$(dot-target).d)
+
+###
+# filename of target with directory and extension stripped
+basetarget = $(basename $(notdir $@))
+
+###
+# filename of first prerequisite with directory and extension stripped
+baseprereq = $(basename $(notdir $<))
 
 ###
 # Escape single quote for use in echo statements
 escsq = $(subst $(squote),'\$(squote)',$1)
 
 ###
+# Easy method for doing a status message
+       kecho := :
+ quiet_kecho := echo
+silent_kecho := :
+kecho := $($(quiet)kecho)
+
+###
 # filechk is used to check if the content of a generated file is updated.
 # Sample usage:
 # define filechk_sample
@@ -33,13 +52,13 @@
 #   to specify a valid file as first prerequisite (often the kbuild file)
 define filechk
 	$(Q)set -e;				\
-	echo '  CHK     $@';			\
+	$(kecho) '  CHK     $@';		\
 	mkdir -p $(dir $@);			\
 	$(filechk_$(1)) < $< > $@.tmp;		\
 	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
 		rm -f $@.tmp;			\
 	else					\
-		echo '  UPD     $@';		\
+		$(kecho) '  UPD     $@';	\
 		mv -f $@.tmp $@;		\
 	fi
 endef
@@ -48,38 +67,95 @@
 # gcc support functions
 # See documentation in Documentation/kbuild/makefiles.txt
 
-# as-option
-# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
+# cc-cross-prefix
+# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
+# Return first prefix where a prefix$(CC) is found in PATH.
+# If no $(CC) found in PATH with listed prefixes return nothing
+cc-cross-prefix =  \
+	$(word 1, $(foreach c,$(1),                                   \
+		$(shell set -e;                                       \
+		if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
+			echo $(c);                                    \
+		fi)))
 
-as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
-	     -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
-	     else echo "$(2)"; fi ;)
+# output directory for tests below
+TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
+
+# try-run
+# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
+# Exit code chooses option. "$$TMP" is can be used as temporary file and
+# is automatically cleaned up.
+try-run = $(shell set -e;		\
+	TMP="$(TMPOUT).$$$$.tmp";	\
+	TMPO="$(TMPOUT).$$$$.o";	\
+	if ($(1)) >/dev/null 2>&1;	\
+	then echo "$(2)";		\
+	else echo "$(3)";		\
+	fi;				\
+	rm -f "$$TMP" "$$TMPO")
+
+# as-option
+# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
+
+as-option = $(call try-run,\
+	$(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
+
+# as-instr
+# Usage: cflags-y += $(call as-instr,instr,option1,option2)
+
+as-instr = $(call try-run,\
+	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
 
 # cc-option
-# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
+# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 
-cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
-             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
+cc-option = $(call try-run,\
+	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2))
 
 # cc-option-yn
-# Usage: flag := $(call cc-option-yn, -march=winchip-c6)
-cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
-                > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
+# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
+cc-option-yn = $(call try-run,\
+	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n)
 
 # cc-option-align
 # Prefix align with either -falign or -malign
 cc-option-align = $(subst -functions=0,,\
 	$(call cc-option,-falign-functions=0,-malign-functions=0))
 
+# cc-disable-warning
+# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
+cc-disable-warning = $(call try-run,\
+	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -xc /dev/null -o "$$TMP",-Wno-$(strip $(1)))
+
 # cc-version
-# Usage gcc-ver := $(call cc-version, $(CC))
-cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
-              $(if $(1), $(1), $(CC)))
+# Usage gcc-ver := $(call cc-version)
+cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
+
+# cc-fullversion
+# Usage gcc-ver := $(call cc-fullversion)
+cc-fullversion = $(shell $(CONFIG_SHELL) \
+	$(srctree)/scripts/gcc-version.sh -p $(CC))
 
 # cc-ifversion
 # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
-cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
-                       echo $(3); fi;)
+cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
+
+# cc-ldoption
+# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
+cc-ldoption = $(call try-run,\
+	$(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
+
+# ld-option
+# Usage: LDFLAGS += $(call ld-option, -X)
+ld-option = $(call try-run,\
+	$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
+
+# ar-option
+# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
+# Important: no spaces around options
+ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
+
+######
 
 ###
 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
@@ -87,20 +163,29 @@
 # $(Q)$(MAKE) $(build)=dir
 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 
+###
 # Shorthand for $(Q)$(MAKE) -f scripts/Kbuild.klibc obj=
 # Usage:
 # $(Q)$(MAKE) $(klibc)=dir
 klibc := -f $(srctree)/scripts/Kbuild.klibc obj
 
-# Prefix -I with $(srctree) if it is not an absolute path
-addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
+# Prefix -I with $(srctree) if it is not an absolute path.
+# skip if -I has no parameter
+addtree = $(if $(patsubst -I%,%,$(1)), \
+$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
+
 # Find all -I options and call addtree
 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 
-# If quiet is set, only print short version of command
+# echo command.
+# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
+echo-cmd = $(if $($(quiet)cmd_$(1)),\
+	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
+
+# printing commands
 cmd = @$(echo-cmd) $(cmd_$(1))
 
-# Add $(obj)/ for paths that is not absolute
+# Add $(obj)/ for paths that are not absolute
 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 
 ###
@@ -112,42 +197,82 @@
 # See Documentation/kbuild/makefiles.txt for more info
 
 ifneq ($(KBUILD_NOCMDDEP),1)
-# Check if both arguments has same arguments. Result in empty string if equal
+# Check if both arguments has same arguments. Result is empty string if equal.
 # User may override this check using make KBUILD_NOCMDDEP=1
-arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
+arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
+                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
+else
+arg-check = $(if $(strip $(cmd_$@)),,1)
 endif
 
-# echo command. Short version is $(quiet) equals quiet, otherwise full command
-echo-cmd = $(if $($(quiet)cmd_$(1)), \
-	echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
-
+# >'< substitution is for echo to work,
+# >$< substitution to preserve $ when reloading .cmd file
+# note: when using inline perl scripts [perl -e '...$$t=1;...']
+# in $(cmd_xxx) double $$ your perl vars
 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
 
-# function to only execute the passed command if necessary
-# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
-# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
-#
-if_changed = $(if $(strip $(filter-out $(PHONY),$?)          \
-		$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
-	@set -e; \
-	$(echo-cmd) $(cmd_$(1)); \
-	echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)
+# Find any prerequisites that is newer than target or that does not exist.
+# PHONY targets skipped in both cases.
+any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 
-# execute the command and also postprocess generated .d dependencies
-# file
-if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?)  \
-		$(filter-out FORCE $(wildcard $^),$^)    \
-	$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),     \
-	@set -e; \
-	$(echo-cmd) $(cmd_$(1)); \
-	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \
-	rm -f $(depfile); \
-	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
+# Execute command if command has changed or prerequisite(s) are updated.
+#
+if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
+	@set -e;                                                             \
+	$(echo-cmd) $(cmd_$(1));                                             \
+	echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
+
+# Execute the command and also postprocess generated .d dependencies file.
+if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
+	@set -e;                                                             \
+	$(echo-cmd) $(cmd_$(1));                                             \
+	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
+	rm -f $(depfile);                                                    \
+	mv -f $(dot-target).tmp $(dot-target).cmd)
 
 # Usage: $(call if_changed_rule,foo)
-# will check if $(cmd_foo) changed, or any of the prequisites changed,
-# and if so will execute $(rule_foo)
-if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?)            \
-			$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
-			@set -e; \
-			$(rule_$(1)))
+# Will check if $(cmd_foo) or any of the prerequisites changed,
+# and if so will execute $(rule_foo).
+if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
+	@set -e;                                                             \
+	$(rule_$(1)))
+
+###
+# why - tell why a a target got build
+#       enabled by make V=2
+#       Output (listed in the order they are checked):
+#          (1) - due to target is PHONY
+#          (2) - due to target missing
+#          (3) - due to: file1.h file2.h
+#          (4) - due to command line change
+#          (5) - due to missing .cmd file
+#          (6) - due to target not in $(targets)
+# (1) PHONY targets are always build
+# (2) No target, so we better build it
+# (3) Prerequisite is newer than target
+# (4) The command line stored in the file named dir/.target.cmd
+#     differed from actual command line. This happens when compiler
+#     options changes
+# (5) No dir/.target.cmd file (used to store command line)
+# (6) No dir/.target.cmd file and target not listed in $(targets)
+#     This is a good hint that there is a bug in the kbuild file
+ifeq ($(KBUILD_VERBOSE),2)
+why =                                                                        \
+    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
+        $(if $(wildcard $@),                                                 \
+            $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
+                $(if $(arg-check),                                           \
+                    $(if $(cmd_$@),- due to command line change,             \
+                        $(if $(filter $@, $(targets)),                       \
+                            - due to missing .cmd file,                      \
+                            - due to $(notdir $@) not in $$(targets)         \
+                         )                                                   \
+                     )                                                       \
+                 )                                                           \
+             ),                                                              \
+             - due to target missing                                         \
+         )                                                                   \
+     )
+
+echo-why = $(call escsq, $(strip $(why)))
+endif
diff --git a/scripts/Kbuild.klibc b/scripts/Kbuild.klibc
index fb399f5..f500d53 100644
--- a/scripts/Kbuild.klibc
+++ b/scripts/Kbuild.klibc
@@ -381,7 +381,7 @@
 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------
 
-.PHONY: FORCE
+PHONY += FORCE
 
 FORCE: