Makefile: remove and create libgit.a from scratch.

Foolishly I renamed diff.o around which caused an old diff.o
taken out of libgit.a and got linked into resulting binary and
exhibited mysterious breakage for many people.  This borrows
from the kernel Makefile (scripts/Makefile.build) to first remove
the target and then recreate.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Makefile b/Makefile
index d9a3a82..809383c 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -575,7 +575,7 @@ $(patsubst git-%$X,%.o,$(PROGRAMS)): $(GITLIBS)
 $(DIFF_OBJS): diffcore.h
 
 $(LIB_FILE): $(LIB_OBJS)
-       $(AR) rcs $@ $(LIB_OBJS)
+       rm -f $@ && $(AR) rcs $@ $(LIB_OBJS)
 
 XDIFF_OBJS=xdiff/xdiffi.o xdiff/xprepare.o xdiff/xutils.o xdiff/xemit.o