Merge branch 'np/delta' into next

* np/delta:
replace adler32 with Rabin's polynomial in diff-delta

diff --combined Makefile
index 4416af9bb05c710cf6577540f6f1edc94c93604b,38c980bfb6841847ce14cedae3012d155e243218..576067fafbd9fab97fa555ef7272d88e6a580892
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -199,12 -199,12 +199,12 @@@ LIB_H = 
        tree-walk.h log-tree.h
  
  DIFF_OBJS = \
 -      diff-lib.o diffcore-break.o diffcore-order.o \
 +      diff.o diff-lib.o diffcore-break.o diffcore-order.o \
        diffcore-pickaxe.o diffcore-rename.o tree-diff.o combine-diff.o \
        diffcore-delta.o log-tree.o
  
  LIB_OBJS = \
 -      blob.o commit.o connect.o csum-file.o \
 +      blob.o commit.o connect.o csum-file.o cache-tree.o \
        date.o diff-delta.o entry.o exec_cmd.o ident.o index.o \
        object.o pack-check.o patch-delta.o path.o pkt-line.o \
        quote.o read-cache.o refs.o run-command.o \
@@@ -214,7 -214,7 +214,7 @@@
        $(DIFF_OBJS)
  
  BUILTIN_OBJS = \
 -      builtin-log.o builtin-help.o
 +      builtin-log.o builtin-help.o builtin-count.o
  
  GITLIBS = $(LIB_FILE) $(XDIFF_LIB)
  LIBS = $(GITLIBS) -lz
@@@ -575,12 -575,12 +575,12 @@@ $(patsubst git-%$X,%.o,$(PROGRAMS)): $(
  $(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
  
  $(XDIFF_LIB): $(XDIFF_OBJS)
 -      $(AR) rcs $@ $(XDIFF_OBJS)
 +      rm -f $@ && $(AR) rcs $@ $(XDIFF_OBJS)
  
  
  doc:
@@@ -609,11 -609,8 +609,11 @@@ test-date$X: test-date.c date.o ctype.
        $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) test-date.c date.o ctype.o
  
  test-delta$X: test-delta.c diff-delta.o patch-delta.o
-       $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $^ -lz
+       $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $^
  
 +test-dump-cache-tree$X: dump-cache-tree.o $(GITLIBS)
 +      $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
 +
  check:
        for i in *.c; do sparse $(ALL_CFLAGS) $(SPARSE_FLAGS) $$i || exit; done