Merge branch 'jc/symref' into next

* jc/symref:
  core.prefersymlinkrefs: use symlinks for .git/HEAD

diff --combined Makefile
index 2374335,cb6bb72..ecbdde6
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -28,8 -28,8 +28,8 @@@ all
  #
  # Define NO_SETENV if you don't have setenv in the C library.
  #
- # Define USE_SYMLINK_HEAD if you want .git/HEAD to be a symbolic link.
- # Don't enable it on Windows.
+ # Define NO_SYMLINK_HEAD if you never want .git/HEAD to be a symbolic link.
+ # Enable it on Windows.  By default, symrefs are still used.
  #
  # Define PPC_SHA1 environment variable when running make to make use of
  # a bundled SHA1 routine optimized for PowerPC.
@@@ -115,13 -115,13 +115,13 @@@ SPARSE_FLAGS = -D__BIG_ENDIAN__ -D__pow
  SCRIPT_SH = \
        git-add.sh git-bisect.sh git-branch.sh git-checkout.sh \
        git-cherry.sh git-clean.sh git-clone.sh git-commit.sh \
 -      git-count-objects.sh git-diff.sh git-fetch.sh \
 +      git-fetch.sh \
        git-format-patch.sh git-ls-remote.sh \
        git-merge-one-file.sh git-parse-remote.sh \
 -      git-prune.sh git-pull.sh git-push.sh git-rebase.sh \
 +      git-prune.sh git-pull.sh git-rebase.sh \
        git-repack.sh git-request-pull.sh git-reset.sh \
        git-resolve.sh git-revert.sh git-rm.sh git-sh-setup.sh \
 -      git-tag.sh git-verify-tag.sh git-whatchanged.sh \
 +      git-tag.sh git-verify-tag.sh \
        git-applymbox.sh git-applypatch.sh git-am.sh \
        git-merge.sh git-merge-stupid.sh git-merge-octopus.sh \
        git-merge-resolve.sh git-merge-ours.sh git-grep.sh \
@@@ -139,7 -139,7 +139,7 @@@ SCRIPT_PYTHON = 
  SCRIPTS = $(patsubst %.sh,%,$(SCRIPT_SH)) \
          $(patsubst %.perl,%,$(SCRIPT_PERL)) \
          $(patsubst %.py,%,$(SCRIPT_PYTHON)) \
 -        git-cherry-pick git-show git-status
 +        git-cherry-pick git-status
  
  # The ones that do not have to link with lcrypto, lz nor xdiff.
  SIMPLE_PROGRAMS = \
@@@ -167,8 -167,7 +167,8 @@@ PROGRAMS = 
        git-name-rev$X git-pack-redundant$X git-repo-config$X git-var$X \
        git-describe$X git-merge-tree$X git-blame$X git-imap-send$X
  
 -BUILT_INS = git-log$X
 +BUILT_INS = git-log$X git-whatchanged$X git-show$X \
 +      git-count-objects$X git-diff$X git-push$X
  
  # what 'all' will build and 'install' will install, in gitexecdir
  ALL_PROGRAMS = $(PROGRAMS) $(SIMPLE_PROGRAMS) $(SCRIPTS)
@@@ -205,7 -204,7 +205,7 @@@ DIFF_OBJS = 
        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 \
@@@ -215,8 -214,7 +215,8 @@@
        $(DIFF_OBJS)
  
  BUILTIN_OBJS = \
 -      builtin-log.o builtin-help.o
 +      builtin-log.o builtin-help.o builtin-count.o builtin-diff.o \
 +      builtin-push.o builtin-grep.o
  
  GITLIBS = $(LIB_FILE) $(XDIFF_LIB)
  LIBS = $(GITLIBS) -lz
@@@ -265,6 -263,7 +265,7 @@@ ifeq ($(uname_O),Cygwin
        NO_D_TYPE_IN_DIRENT = YesPlease
        NO_D_INO_IN_DIRENT = YesPlease
        NO_STRCASESTR = YesPlease
+       NO_SYMLINK_HEAD = YesPlease
        NEEDS_LIBICONV = YesPlease
        # There are conflicting reports about this.
        # On some boxes NO_MMAP is needed, and not so elsewhere.
@@@ -388,6 -387,9 +389,9 @@@ endi
  ifdef NO_D_INO_IN_DIRENT
        ALL_CFLAGS += -DNO_D_INO_IN_DIRENT
  endif
+ ifdef NO_SYMLINK_HEAD
+       ALL_CFLAGS += -DNO_SYMLINK_HEAD
+ endif
  ifdef NO_STRCASESTR
        COMPAT_CFLAGS += -DNO_STRCASESTR
        COMPAT_OBJS += compat/strcasestr.o
@@@ -507,6 -509,9 +511,6 @@@ $(patsubst %.py,%,$(SCRIPT_PYTHON)) : 
  git-cherry-pick: git-revert
        cp $< $@
  
 -git-show: git-whatchanged
 -      cp $< $@
 -
  git-status: git-commit
        cp $< $@
  
@@@ -608,10 -613,7 +612,10 @@@ 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

diff --combined cache.h
index a0cf8ca,9d0ddcf..d186b44
--- 1/cache.h
--- 2/cache.h
+++ b/cache.h
@@@ -114,7 -114,6 +114,7 @@@ static inline unsigned int create_ce_mo
  
  extern struct cache_entry **active_cache;
  extern unsigned int active_nr, active_alloc, active_cache_changed;
 +extern struct cache_tree *active_cache_tree;
  
  #define GIT_DIR_ENVIRONMENT "GIT_DIR"
  #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
@@@ -170,7 -169,7 +170,7 @@@ extern void rollback_index_file(struct 
  /* Environment bits from configuration mechanism */
  extern int trust_executable_bit;
  extern int assume_unchanged;
- extern int only_use_symrefs;
+ extern int prefer_symlink_refs;
  extern int warn_ambiguous_refs;
  extern int diff_rename_limit_default;
  extern int shared_repository;
@@@ -252,7 -251,6 +252,7 @@@ extern void *read_object_with_reference
                                        unsigned char *sha1_ret);
  
  const char *show_date(unsigned long time, int timezone);
 +const char *show_rfc2822_date(unsigned long time, int timezone);
  int parse_date(const char *date, char *buf, int bufsize);
  void datestamp(char *buf, int bufsize);
  unsigned long approxidate(const char *);