gstramer: fixes flex version parsing problem

Fixes Homebrew/homebrew#13523.
Closes Homebrew/homebrew#13524.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/gstreamer.rb

@@ -9,6 +9,13 @@ class Gstreamer < Formula
   depends_on 'gettext'
   depends_on 'glib'
 
+  # Fix sed version detection for 10.8
+  # Reported and fixed upstream:
+  # https://bugzilla.gnome.org/show_bug.cgi?id=680428
+  def patches
+    DATA
+  end
+
   def install
     # Look for plugins in HOMEBREW_PREFIX/lib/gstreamer-0.10 instead of
     # HOMEBREW_PREFIX/Cellar/gstreamer/0.10/lib/gstreamer-0.10, so we'll find
@@ -27,3 +34,18 @@ class Gstreamer < Formula
     system "make install"
   end
 end
+
+__END__
+diff --git a/configure b/configure
+index 0af896d..20e6576 100755
+--- a/configure
++++ b/configure
+@@ -21304,7 +21304,7 @@ fi
+   fi
+ 
+         flex_min_version=2.5.31
+-  flex_version=`$FLEX_PATH --version | head -n 1 | sed 's/^.* //' | sed 's/[a-zA-Z]*$//' | cut -d' ' -f1`
++  flex_version=`$FLEX_PATH --version | head -n 1 | awk '{print $2'}`
+   { $as_echo "$as_me:${as_lineno-$LINENO}: checking flex version $flex_version >= $flex_min_version" >&5
+ $as_echo_n "checking flex version $flex_version >= $flex_min_version... " >&6; }
+   if perl -w <<EOF