Merge branch 'sp/gc'

* sp/gc:
Use 'repack -a -d -l' instead of 'repack -a -d' in git-gc
everyday: replace a few 'prune' and 'repack' with 'gc'
Create 'git gc' to perform common maintenance operations.

diff --combined Makefile
index f862170b1f8297b397022764a5937ff4d466b87d,12f4bd22e7324e6b6ba39a6c9e8ae709cdcc1789..775ffaac27d7382df9db84d226603854295045d6
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -157,7 -157,7 +157,7 @@@ BASIC_LDFLAGS 
  SCRIPT_SH = \
        git-bisect.sh git-checkout.sh \
        git-clean.sh git-clone.sh git-commit.sh \
-       git-fetch.sh \
+       git-fetch.sh git-gc.sh \
        git-ls-remote.sh \
        git-merge-one-file.sh git-parse-remote.sh \
        git-pull.sh git-rebase.sh \
@@@ -360,8 -360,8 +360,8 @@@ ifeq ($(uname_O),Cygwin
        NO_FAST_WORKING_DIRECTORY = UnfortunatelyYes
        # There are conflicting reports about this.
        # On some boxes NO_MMAP is needed, and not so elsewhere.
 -      # Try uncommenting this if you see things break -- YMMV.
 -      # NO_MMAP = YesPlease
 +      # Try commenting this out if you suspect MMAP is more efficient
 +      NO_MMAP = YesPlease
        NO_IPV6 = YesPlease
        X = .exe
  endif