Use gcc-generated dependency files if we can (GNU Make and gcc required).

* Makefile.in: If AUTO_DEPEND is defined, make gcc generate
dependency files in deps/. Include those files into Makefile.

* config.in: Generated (AUTO_DEPEND).

* configure.in: --enable-autodepend is new.  Check for GNU Make
and that gcc supports -MMD -MF. Define AUTO_DEPEND if we can use
gcc and GNU make to generate dependencies.

3 files changed, 53 insertions, 21 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index fb1093ae1f8..37ff8860779 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2009-11-14  Jan Djärv  <jan.h.d@swipnet.se>
+
+        * Makefile.in: If AUTO_DEPEND is defined, make gcc generate
+        dependency files in deps/. Include those files into Makefile.
+
+        * config.in: Generated (AUTO_DEPEND).
+
 2009-11-13  Michael Albinus  <michael.albinus@gmx.de>
 
         * dbusbind.c (Vdbus_registered_objects_table): Renamed from
diff --git a/src/Makefile.in b/src/Makefile.in
index adb1c817f30..e6fa649e682 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -79,6 +79,10 @@ SHELL=/bin/sh
 #define NOT_C_CODE
 #include "config.h"
 
+#ifdef AUTO_DEPEND
+DEPFLAGS = -MMD -MF deps/$*.d
+#endif
+
 /* Do not let the file name mktime.c get messed up.  */
 #ifdef mktime
 #undef mktime
@@ -257,13 +261,19 @@ DBUS_OBJ = dbusbind.o
 
 /* C_SWITCH_X_SITE must come before C_SWITCH_X_MACHINE and C_SWITCH_X_SYSTEM
    since it may have -I options that should override those two.  */
-ALL_CFLAGS=-Demacs -DHAVE_CONFIG_H $(MYCPPFLAGS) -I. -I${srcdir} C_SWITCH_MACHINE C_SWITCH_SYSTEM C_SWITCH_X_SITE C_SWITCH_X_MACHINE C_SWITCH_X_SYSTEM C_SWITCH_SYSTEM_TEMACS ${CFLAGS_SOUND} ${RSVG_CFLAGS} ${DBUS_CFLAGS} ${CFLAGS} @FREETYPE_CFLAGS@ @FONTCONFIG_CFLAGS@ @LIBOTF_CFLAGS@ @M17N_FLT_CFLAGS@
+ALL_CFLAGS=-Demacs -DHAVE_CONFIG_H $(MYCPPFLAGS) -I. -I${srcdir} C_SWITCH_MACHINE C_SWITCH_SYSTEM C_SWITCH_X_SITE C_SWITCH_X_MACHINE C_SWITCH_X_SYSTEM C_SWITCH_SYSTEM_TEMACS ${CFLAGS_SOUND} ${RSVG_CFLAGS} ${DBUS_CFLAGS} ${CFLAGS} @FREETYPE_CFLAGS@ @FONTCONFIG_CFLAGS@ @LIBOTF_CFLAGS@ @M17N_FLT_CFLAGS@ ${DEPFLAGS}
 ALL_OBJC_CFLAGS=$(ALL_CFLAGS) @GNU_OBJC_CFLAGS@
 
 .SUFFIXES: .m
 .c.o:
+#ifdef AUTO_DEPEND
+        @test -d deps || mkdir deps
+#endif
         $(CC) -c $(CPPFLAGS) $(ALL_CFLAGS) $<
 .m.o:
+#ifdef AUTO_DEPEND
+        @test -d deps || mkdir deps
+#endif
         $(CC) -c $(CPPFLAGS) $(ALL_OBJC_CFLAGS) $<
 
 #ifndef LIBX11_SYSTEM
@@ -958,7 +968,7 @@ temacs${EXEEXT}: $(LOCALCPP) $(STARTFILES) stamp-oldxmenu ${obj} ${otherobj} pre
 /* We do not use ALL_LDFLAGS because LD_SWITCH_SYSTEM and LD_SWITCH_MACHINE
    often contain options that have to do with using Emacs''s crt0,
    which are only good with temacs.  */
-prefix-args${EXEEXT}: prefix-args.c $(config_h)
+prefix-args${EXEEXT}: prefix-args.o $(config_h)
         $(CC) $(ALL_CFLAGS) $(LDFLAGS) ${srcdir}/prefix-args.c -o prefix-args
 
 #if defined (HAVE_X_WINDOWS) && defined (HAVE_X11) && defined (HAVE_MENUS) && ! defined (USE_GTK)
@@ -1024,6 +1034,11 @@ stamp-oldxmenu:
         @echo "Please run the `configure' script again."
         exit 1
 
+ecrt0.o: ecrt0.c $(config_h)
+        CRT0_COMPILE ${srcdir}/ecrt0.c
+doc.o: buildobj.h
+
+#ifndef AUTO_DEPEND
 /* Nearly all the following files depend on lisp.h,
    but it is not included as a dependency because
    it is so often changed in ways that do not require any recompilation
@@ -1056,8 +1071,6 @@ cm.o: cm.c frame.h cm.h termhooks.h termchar.h lisp.h $(config_h)
 cmds.o: cmds.c syntax.h buffer.h character.h commands.h window.h lisp.h $(config_h) \
         msdos.h dispextern.h keyboard.h keymap.h
 pre-crt0.o: pre-crt0.c
-ecrt0.o: ecrt0.c $(config_h)
-        CRT0_COMPILE ${srcdir}/ecrt0.c
 dbusbind.o: dbusbind.c termhooks.h frame.h keyboard.h lisp.h $(config_h)
 dired.o: dired.c commands.h buffer.h lisp.h $(config_h) character.h charset.h \
    coding.h regex.h systime.h blockinput.h atimer.h
@@ -1066,8 +1079,7 @@ dispnew.o: dispnew.c systime.h commands.h process.h frame.h \
    disptab.h indent.h $(INTERVALS_H) \
    xterm.h blockinput.h atimer.h character.h msdos.h composite.h keyboard.h \
    syssignal.h lisp.h $(config_h)
-doc.o: doc.c lisp.h $(config_h) epaths.h buffer.h keyboard.h keymap.h character.h \
-   buildobj.h
+doc.o: doc.c lisp.h $(config_h) epaths.h buffer.h keyboard.h keymap.h character.h
 doprnt.o: doprnt.c character.h lisp.h $(config_h)
 dosfns.o: buffer.h termchar.h termhooks.h frame.h blockinput.h window.h \
    msdos.h dosfns.h dispextern.h charset.h coding.h atimer.h systime.h \
@@ -1252,6 +1264,8 @@ intervals.o: intervals.c buffer.h $(INTERVALS_H) keyboard.h puresize.h \
 textprop.o: textprop.c buffer.h window.h dispextern.h $(INTERVALS_H) \
         lisp.h $(config_h)
 
+#endif /* ! AUTO_DEPEND */
+
 /* System-specific programs to be made.
    OTHER_FILES
    select which of these should be compiled.  */
@@ -1287,6 +1301,7 @@ mostlyclean:
         rm -f buildobj.h
 clean: mostlyclean
         rm -f emacs-*.*.*${EXEEXT} emacs${EXEEXT}
+        -rm -rf deps
 #ifdef HAVE_NS
         rm -fr ${ns_appdir}
 #endif
@@ -1385,3 +1400,8 @@ bootstrap-emacs${EXEEXT}: temacs${EXEEXT}
 #endif /* ! defined (CANNOT_DUMP) */
         @: Compile some files earlier to speed up further compilation.
         cd ../lisp; $(MAKE) $(MFLAGS) compile-first EMACS=${bootstrap_exe}
+
+#ifdef AUTO_DEPEND
+ALLOBJS=$(STARTFILES) ${obj} ${otherobj} prefix-args.o
+-include $(ALLOBJS:%.o=deps/%.d)
+#endif
diff --git a/src/config.in b/src/config.in
index 4241b3eee41..04b6de5714d 100644
--- a/src/config.in
+++ b/src/config.in
@@ -27,6 +27,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define EMACS_CONFIG_H
 
 
+/* Generate dependencies with gcc. */
+#undef AUTO_DEPEND
+
 /* Define to 1 if the mktime function is broken. */
 #undef BROKEN_MKTIME
 
@@ -828,6 +831,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* Define to 1 if you don't have struct exception in math.h. */
 #undef NO_MATHERR
 
+/* Define to 1 if `NSInteger' is defined. */
+#undef NS_HAVE_NSINTEGER
+
 /* Define to 1 if you are using NS windowing under MacOS X. */
 #undef NS_IMPL_COCOA
 
@@ -921,21 +927,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    XPointer or XPointer*. */
 #undef XRegisterIMInstantiateCallback_arg6
 
-/* Define to 1 if on AIX 3.
-   System headers sometimes define this.
-   We just want to avoid a redefinition error message.  */
-#ifndef _ALL_SOURCE
-# undef _ALL_SOURCE
-#endif
-
 /* Number of bits in a file offset, on hosts where this is settable. */
 #undef _FILE_OFFSET_BITS
 
-/* Enable GNU extensions on systems that have them.  */
-#ifndef _GNU_SOURCE
-# undef _GNU_SOURCE
-#endif
-
 /* Define to 1 to make fseeko visible on some hosts (e.g. glibc 2.2). */
 #undef _LARGEFILE_SOURCE
 
@@ -952,16 +946,27 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* Define to 1 if you need to in order for `stat' and other things to work. */
 #undef _POSIX_SOURCE
 
-/* Enable extensions on Solaris.  */
-#ifndef __EXTENSIONS__
-# undef __EXTENSIONS__
+/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# undef _ALL_SOURCE
 #endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# undef _GNU_SOURCE
+#endif
+/* Enable threading extensions on Solaris.  */
 #ifndef _POSIX_PTHREAD_SEMANTICS
 # undef _POSIX_PTHREAD_SEMANTICS
 #endif
+/* Enable extensions on HP NonStop.  */
 #ifndef _TANDEM_SOURCE
 # undef _TANDEM_SOURCE
 #endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+
 
 /* Define to rpl_ if the getopt replacement functions and variables should be
    used. */