[PATCH] Build commands through object files

Separate the process of building the commands to compilation and
linkage. This makes it more consistent with the library objects, is the
traditional thing to do, and significantly speeds up the subsequent
rebuilds, especially for us the people who develop git on 300MHz
notebooks.

Ported from Cogito.

Signed-off-by: Petr Baudis <pasky@ucw.cz>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Makefile

@@ -137,13 +137,14 @@ CFLAGS += '-DSHA1_HEADER=$(SHA1_HEADER)'
 all: $(PROG)
 
 
-git-%: %.c $(LIB_FILE)
-	$(CC) $(CFLAGS) -o $@ $(filter %.c,$^) $(LIBS)
-
-git-http-pull: pull.c
-git-local-pull: pull.c
-git-ssh-pull: rsh.c pull.c
-git-ssh-push: rsh.c
+.PRECIOUS: %.o
+git-%: %.o $(LIB_FILE)
+	$(CC) $(CFLAGS) -o $@ $(filter %.o,$^) $(LIBS)
+
+git-http-pull: pull.o
+git-local-pull: pull.o
+git-ssh-pull: rsh.o pull.o
+git-ssh-push: rsh.o
 
 git-http-pull: LIBS += -lcurl
 git-rev-list: LIBS += -lssl