Add patch to work around unusual shell script error. Possible bug in /bin/sh?

Fix discovered by IWAMOTO Toshihiro <iwamoto@sat.t.u-tokyo.ac.jp>.

lang/librep/files/patch-sum

@@ -1,5 +1,3 @@
 
-This placeholder file is generated by the ``makepatchsum'' target
-whenever the patches directory is empty or missing. Its purpose
-is to ensure that the presence of any obsolete patches will cause
-the proper error to be emitted at build time.
+
+MD5 (patch-aa) = 78f1b645f5b6f5b9a17a8b6ad0f25477

lang/librep/patches/patch-aa

@@ -0,0 +1,16 @@
+$NetBSD: patch-aa,v 1.4 2000/10/29 20:33:45 jlam Exp $
+
+--- install-aliases.orig	Tue Oct 17 20:52:03 2000
++++ install-aliases
+@@ -76,8 +76,9 @@
+ 	    ;;
+ 	  *)
+ 	    # make sure links are relative to their own directory
+-	    src=`strip_common_prefix "$dest" "$src"`
+-	    ln -s "${src}${suf}" "${destroot}/${dest}${suf}"
++	    # pkgsrc: not sure why this change is necessary...bug in /bin/sh?
++	    src1=`strip_common_prefix "$dest" "$src"`
++	    ln -s "${src1}${suf}" "${destroot}/${dest}${suf}"
+ 	    ;;
+ 	esac
+       fi