Makefile: autobuild dependency rules
This uses gcc to generate dependency rules for each `.o` file, based on the
corresponding `.c` file, into a new set of `.d` files (which are also defined
to depend on the same set of source files as their `.o` files).
Result:
* all objectfile dependencies are correctly calculated
* only the necessary dependencies are recalculated when a sourcefile is updated
Inspiration for the build rules:
* http://www.gnu.org/software/make/manual/make.html#Automatic-Prerequisites
* http://make.paulandlesley.org/autodep.html
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
diff --git a/Makefile b/Makefile
index d1950cb..faf7b98 100644
--- a/Makefile
+++ b/Makefile
@@ -13,6 +13,13 @@
-include cgit.conf
+#
+# Define a pattern rule for automatic dependency building
+#
+%.d: %.c
+ $(CC) $(CFLAGS) -MM $< | sed -e 's/\($*\)\.o:/\1.o $@:/g' >$@
+
+
EXTLIBS = git/libgit.a git/xdiff/lib.a -lz -lcrypto
OBJECTS =
OBJECTS += cache.o
@@ -61,6 +68,8 @@
$(OBJECTS): git/xdiff/lib.a git/libgit.a VERSION
+-include $(OBJECTS:.o=.d)
+
git/xdiff/lib.a: | git
git/libgit.a: | git
@@ -84,7 +93,7 @@
rm -f $(CGIT_SCRIPT_PATH)/cgit.png
clean:
- rm -f cgit VERSION *.o
+ rm -f cgit VERSION *.o *.d
cd git && $(MAKE) clean
distclean: clean