make: on-the-fly dependency generation

- support on-the-fly dependency file generation with gcc >=3.0
 (the dependency files are generated while compiling the object
 file, eliminating another gcc+sed invocation)

- support for using makedepend -f-  for generating dependencies
 E.g.: make cfg MKDEP="makedepend -f-". In general gcc should be
 preferred if available (use this if you don't have gcc and your
 compiler doesn't generate good deps).
(cherry picked from commit 5a9014ee4977c6afbc4b0cf65a9fad6237c2e2a6)
(cherry picked from commit 929598a19dfb09efcfcbb1aee57a83f45b12592f)

Makefile.defs

@@ -74,6 +74,9 @@
 #              from the host (andrei)
 #  2009-10-01  use -fsigned-char for gcc on ppc, ppc64, arm and arm6
 #              (on those archs char is unsigned by default) (andrei)
+#  2010-03-10  added CC_MKDEP_OPTS, which contains to the list of options
+#               needed to generate dependencies on-the-fly while compiling
+#               or is empty if the compiler doesn't support it (andrei)
 
 quiet?=$(if $(filter 1 yes on,$(Q)),silent,verbose)
 
@@ -350,7 +353,7 @@ ifneq (,$(findstring gcc, $(CC_LONGVER)))
 #				 	 -e 's/^[^0-9].*\([0-9][0-9]*\.[0-9][0-9]*\).*/\1/')
 	# sed with POSIX.1 regex doesn't support |, + or ? 
         # (darwin, solaris ...) => this complicated expression
-	MKDEP=$(CC) -MM 
+	MKDEP=$(CC) -MM -MG
 	#transform gcc version into 2.9x or 3.0
 	CC_SHORTVER:=$(shell echo "$(CC_VER)" | cut -d" " -f 2| \
 				 sed -e 's/[^0-9]*-\(.*\)/\1/'| \
@@ -359,7 +362,11 @@ ifneq (,$(findstring gcc, $(CC_LONGVER)))
 					's/3\.[4-9]/3.4/' -e 's/4\.[0-1]\..*/4.x/' -e \
 					's/4\.[0-1]/4.x/' -e 's/4\.[2-9]\..*/4.2+/' -e \
 					's/4\.[2-9]$$/4.2+/')
-endif
+ifeq (,$(strip $(filter-out 3.0 3.4 4.x 4.2+,$(CC_SHORTVER))))
+	# dependencies can be generated on-the-fly while compiling *.c
+	CC_MKDEP_OPTS=-MMD -MP
+endif # 3.0 <= $(CC_SHORTVER) <= 4.x
+endif # gcc
 
 ifneq (, $(findstring Sun, $(CC_LONGVER)))
 	CC_NAME=suncc
@@ -1946,6 +1953,7 @@ export exported_vars
 saved_fixed_vars:=	MAIN_NAME  CFG_NAME SCR_NAME FLAVOUR INSTALL_FLAVOUR \
 		SRC_NAME RELEASE OS ARCH \
 		C_DEFS DEFS_RM PROFILE CC LD MKDEP MKTAGS LDFLAGS C_INCLUDES \
+		CC_MKDEP_OPTS \
 		MOD_LDFLAGS LIB_LDFLAGS UTILS_LDFLAGS LIB_SONAME LD_RPATH \
 		LIB_SUFFIX LIB_PREFIX \
 		LIBS \

Makefile.rules

@@ -25,6 +25,11 @@
 #              used only for "temporary" defines/includes inside modules or
 #              libs, C_DEFS and C_INCLUDES are used for the common stuff)
 #              (andrei)
+#  2010-03-09  generate dependencies when compiling .o instead of on
+#               include .d and fix build errors when a .h is moved
+#              support for using MKDEP="makedepend-f-"      (andrei)
+#  2010-03-10  support for on the-fly dependency generation (while compiling,
+#               see CC_MKDEP_OPTS)  (andrei)
 
 
 # check if the saved cfg corresponds with the current one
@@ -59,6 +64,19 @@ cmd_CC=$(CC) $(CFLAGS) $(C_INCLUDES) $(INCLUDES) $(C_DEFS) $(DEFS) -c $< -o $@
 cmd_LD=$(LD) $(LDFLAGS) $(objs) $(extra_objs) $(ALL_LIBS) $(SER_RPATH) \
 	-o $(NAME)
 
+ifeq (,$(CC_MKDEP_OPTS))
+# if CCC_MKDEP_OPTS is empty => CC cannot generate dependencies on the fly
+cmd_MKDEP=$(MKDEP) $(filter -D% -I%,$(CFLAGS)) $(C_INCLUDES) $(INCLUDES) \
+			$(C_DEFS) $(DEFS) $< \
+		|  sed	-e 's/\#.*//' -e '/:[ 	]*$$/d' -e '/^[ 	]*$$/d' \
+				-e 's|.*:|$@: $$(wildcard |' -e 's/\([^\\]\)$$/\1)/'> $*.d
+else
+# deps can be generated on the fly by cmd_CC
+cmd_CC+=$(CC_MKDEP_OPTS)
+# no MKDEP command any more
+cmd_MKDEP=
+endif # CC_MKDEP_OPTS
+
 # what will be displayed if quiet==silent
 silent_cmd_CC=CC ($(CC)) [$(strip $(crt_type) $(NAME))]		$@
 silent_cmd_LD=LD ($(LD)) [$(strip $(crt_type) $(NAME))]		$@
@@ -84,9 +102,7 @@ exec_cmd= $(if $($(quiet)_cmd_$(1)),\
 #implicit rules
 %.o:%.c  $(ALLDEP)
 	$(call exec_cmd,CC)
-	@$(MKDEP) $(CFLAGS) $(C_INCLUDES) $(INCLUDES) $(C_DEFS) $(DEFS) $< \
-	|  sed	-e 's/#.*//' -e '/:[ 	]*$$/d' -e '/^[ 	]*$$/d' \
-				-e 's#.*:#$@: $$(wildcard #g' -e 's/\([^\\]\)$$/\1)/'> $*.d
+	@$(call cmd_MKDEP)
 
 # use RPATH and SER_LIBS if needed (make install and the module depends
 # on some ser libs)