t / t4135 / diff-plain.diffon commit userdiff/perl: anchor "sub" and "package" patterns on the left (f12c66b)
   1--- postimage.txt.orig  2010-08-18 20:13:31.432002255 -0500
   2+++ postimage.txt       2010-08-18 20:13:31.432002255 -0500
   3@@ -1 +1 @@
   4-preimage
   5+postimage