Update tests to use test-chmtime

test-lib:
  Make sure test-chmtime has been built before starting.

t4200-rerere:
  Removed non-portable date dependency and avoid touch
  Avoid "test -a" which isn't portable, either

lib-git-svn:
  Use test-chmtime instead of Perl one-liner to poke

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>

t/test-lib.sh

@@ -264,6 +264,12 @@ test -d ../templates/blt || {
 	error "You haven't built things yet, have you?"
 }
 
+if ! test -x ../test-chmtime; then
+	echo >&2 'You need to build test-chmtime:'
+	echo >&2 'Run "make test-chmtime" in the source (toplevel) directory'
+	exit 1
+fi
+
 # Test repository
 test=trash
 rm -fr "$test"