Make git-rerere a builtin

The perl version used modules which are non-standard in some setups.
This patch brings the full power of rerere to a wider audience.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

Makefile

@@ -174,7 +174,6 @@ SCRIPT_SH = \
 
 SCRIPT_PERL = \
 	git-archimport.perl git-cvsimport.perl git-relink.perl \
-	git-rerere.perl \
 	git-cvsserver.perl \
 	git-svnimport.perl git-cvsexportcommit.perl \
 	git-send-email.perl git-svn.perl
@@ -289,6 +288,7 @@ BUILTIN_OBJS = \
 	builtin-push.o \
 	builtin-read-tree.o \
 	builtin-repo-config.o \
+	builtin-rerere.o \
 	builtin-rev-list.o \
 	builtin-rev-parse.o \
 	builtin-rm.o \