gcc precompiled header with proper Automake Dependency Tracking

bar.c

#include "stdafx.h"

foo.c

#include "stdafx.h"

Makefile

COMPILE = gcc
DEPDIR = .deps
am__mv = mv

OBJECTS = foo.o bar.o
all: $(OBJECTS)

# The recipe for stdafx.uptodate ensures that the .gch file is up to date
$(OBJECTS): stdafx.uptodate


# The .gch file MAY remain outdated after changing some include file, because we
# don't make it depend on the headers, because we don't know the dependency
# mechanism used by automake.
# If it's outdated, the rule to create stdafx.uptodate will re-make both
# stdafx.h.gch and stdafx.o
stdafx.o: stdafx.h.gch


# Missing .norecomp file indicates that stdafx.o was recompiled during this run,
# but stdafx.gch was not. Then delete stdafx.h.gch and re-run this rule using
# submake.
# It's optimized to build a clean tarball. Each time you change headers,
# stdafx.o will be compiled twice, but the tradeoff is small, because it will
# use existing precompiled header both times.
stdafx.uptodate: stdafx.o
	rm stdafx.h.gch.norecomp 2>/dev/null && touch stdafx.uptodate && exit; \
	  rm -f stdafx.h.gch && $(MAKE) $(AM_MAKEFLAGS) stdafx.uptodate


# .norecomp file indicates that the .gch file was generated during this run.
# It's normally deleted by the .uptodate rule.
#
# If you explicitly make stdafx.o or make stdafx.h.gch , then it will be deleted
# by the make program as .INTERMEDIATE file, but be wary of buggy make versions
# that fail to delete intermediate files - don't make those two files explicitly.
#
# The '-MD' flag is needed because of:
# Bug 28483 - Dependency tracking should be on by default when copiling .gchs
#
%.gch %.gch.norecomp: %
	$(COMPILE) -MD -c -o $*.gch $*
	rm -f $*.d
	touch $*.gch.norecomp

.INTERMEDIATE: stdafx.h.gch.norecomp

clean:
	rm -f *.gch *.uptodate *.norecomp *.o

.PHONY: all clean


# do what ./configure script does to create the missing .Po files
%.Po:
	@mkdir -p $(DEPDIR)
	@touch $@

# recipe generated by automake
.c.o:
	$(COMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
	$(am__mv) $(DEPDIR)/$*.Tpo $(DEPDIR)/$*.Po

# recipe generated by automake with: libstdafx_a_CFLAGS = -fpch-deps
stdafx.o: stdafx.c
	$(COMPILE) -fpch-deps -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
	$(am__mv) $(DEPDIR)/$*.Tpo $(DEPDIR)/$*.Po


-include ./$(DEPDIR)/stdafx.Po
-include ./$(DEPDIR)/foo.Po
-include ./$(DEPDIR)/bar.Po

stdafx.c

#include "stdafx.h"

stdafx.h

#include <stdio.h>
#include "testheader.h"

testheader.h

// bbb