[PATCH 1 of 2] Add 'shelltools': diff tool detection (try to find GNU diff)

[David Champion]

# HG changeset patch
# User David Champion <dgc at uchicago.edu>
# Date 1246838178 18000
# Node ID 179e4915d30813050fb425b33a4f7c591b4cea50
# Parent  a77c3ee40e4d218d9801b123ddc392072eebedfc
Add 'shelltools': diff tool detection (try to find GNU diff)

diff -r a77c3ee40e4d -r 179e4915d308 tests/test-command-template
--- a/tests/test-command-template	Sun Jul 05 13:59:25 2009 -0500
+++ b/tests/test-command-template	Sun Jul 05 18:56:18 2009 -0500
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+. "$TESTDIR/shelltools"
+
 hg init a
 cd a
 echo a > a
diff -r a77c3ee40e4d -r 179e4915d308 tests/test-highlight
--- a/tests/test-highlight	Sun Jul 05 13:59:25 2009 -0500
+++ b/tests/test-highlight	Sun Jul 05 18:56:18 2009 -0500
@@ -2,6 +2,8 @@
 
 "$TESTDIR/hghave" pygments || exit 80
 
+. "$TESTDIR/shelltools"
+
 cat <<EOF >> $HGRCPATH
 [extensions]
 hgext.highlight =