gnuplot: remove obviated patch

Since glib 2.36 the patch is unnecessary.

Closes Homebrew/homebrew#18900.

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

Formula/gnuplot.rb

@@ -34,12 +34,6 @@ class Gnuplot < Formula
   depends_on 'qt'          if build.include? 'qt'
   depends_on :tex          if build.include? 'latex'
 
-  def patches
-    # see discussion on this cairo issue: https://github.com/fontforge/fontforge/issues/222
-    # and the gnuplot bug report: https://sourceforge.net/p/gnuplot/bugs/1223/
-    DATA
-  end
-
   def install
     # Help configure find libraries
     readline = Formula.factory 'readline'
@@ -80,17 +74,3 @@ class Gnuplot < Formula
     system "#{bin}/gnuplot", "--version"
   end
 end
-
-__END__
-diff --git a/term/cairo.trm b/term/cairo.trm
-index 48fac72..c5d110f 100644
---- a/term/cairo.trm
-+++ b/term/cairo.trm
-@@ -615,6 +615,7 @@ TERM_PUBLIC void cairotrm_options()
-  * Is the 'main' function of the terminal. */
- void cairotrm_init()
- {
-+	g_type_init();
-	cairo_surface_t *surface = NULL;
-
-	FPRINTF((stderr,"Init\n"));