Merge git://repo.or.cz/git-gui into maint

* git://repo.or.cz/git-gui:
  Don't modify CREDITS-FILE if it hasn't changed.

diff --cc git-gui/CREDITS-GEN
index da2c07629e171daf2dafa677cbbb514be815aed9,0000000000000000000000000000000000000000..d1b0f86355ed8e37abe7eefcd2eabddee861178d
mode 100755,000000..100755
--- 1/git-gui/CREDITS-GEN
--- /dev/null
+++ b/git-gui/CREDITS-GEN
@@@ -1,58 -1,0 +1,71 @@@
-       rm -f $CF &&
-       git shortlog -n -s $tip | sed 's/: .*$//' >$CF || exit
 +#!/bin/sh
 +
 +CF=CREDITS-FILE
 +tip=
 +
 +tree_search ()
 +{
 +      head=$1
 +      tree=$2
 +      for p in $(git rev-list --parents --max-count=1 $head 2>/dev/null)
 +      do
 +              test $tree = $(git rev-parse $p^{tree} 2>/dev/null) &&
 +              vn=$(git describe --abbrev=4 $p 2>/dev/null) &&
 +              case "$vn" in
 +              gitgui-[0-9]*) echo $p; break;;
 +              esac
 +      done
 +}
 +
 +generate_credits ()
 +{
 +      tip=$1 &&
-       rm -f $CF &&
-       cp credits $CF || exit
++      rm -f "$2" &&
++      git shortlog -n -s $tip | sed 's/: .*$//' >"$2" || exit
 +}
 +
 +# Always use the tarball credits file if found, just
 +# in case we are somehow contained in a larger git
 +# repository that doesn't actually track our state.
 +# (At least one package manager is doing this.)
 +#
 +# We may be a subproject, so try looking for the merge
 +# commit that supplied this directory content if we are
 +# not at the toplevel.  We probably will always be the
 +# second parent in the commit, but we shouldn't rely on
 +# that fact.
 +#
 +
++credits_tmp=/var/tmp/gitgui-credits-$$
++trap 'rm -f "$credits_tmp"' 0
++
++orig="$credits_tmp"
++
 +if test -f credits
 +then
-       generate_credits $tip || exit
++      orig=credits
 +elif prefix="$(git rev-parse --show-prefix 2>/dev/null)" &&
 +   test -n "$prefix" &&
 +   head=$(git rev-list --max-count=1 HEAD -- . 2>/dev/null) &&
 +   tree=$(git rev-parse --verify "HEAD:$prefix" 2>/dev/null) &&
 +   tip=$(tree_search $head $tree) &&
 +   test -n "$tip"
 +then
-       generate_credits $tip || exit
++      generate_credits $tip "$orig" || exit
 +elif tip="$(git rev-parse --verify HEAD 2>/dev/null)" &&
 +   test -n "$tip"
 +then
++      generate_credits $tip "$orig" || exit
 +else
 +      echo "error: Cannot locate authorship information." >&2
 +      exit 1
 +fi
++
++if test -f "$orig" && cmp -s "$orig" "$CF"
++then
++      : noop
++else
++      rm -f "$CF" &&
++      cat "$orig" >"$CF"
++fi
++