librsync: add MacPorts "inline functions" patch

librsync doesn't correctly export inlined functions:
http://trac.macports.org/ticket/31742

Closes Homebrew/homebrew#10697.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/librsync.rb

@@ -5,6 +5,14 @@ class Librsync < Formula
   homepage 'http://librsync.sourceforge.net/'
   md5 '24cdb6b78f45e0e83766903fd4f6bc84'
 
+  def patches
+    # fixes librsync doesn't correctly export inlined functions:
+    # http://trac.macports.org/ticket/31742
+    # link to upstream bug report:
+    # http://sourceforge.net/tracker/?func=detail&aid=3464437&group_id=56125&atid=479439
+    { :p0 => 'https://trac.macports.org/export/90437/trunk/dports/net/librsync/files/patch-delta.c.diff' }
+  end
+
   def install
     ENV.universal_binary
     system "./configure", "--disable-debug", "--disable-dependency-tracking",