Update GraphicsMagick

GraphicsMagick was derived from ImageMagick, because they share a lot of setup
code. But keeping the ImageMagick formula up-to-date means breaking this one,
so I separated them.

Formula/graphicsmagick.rb

@@ -1,24 +1,63 @@
 require 'formula'
-require "#{File.dirname __FILE__}/imagemagick.rb"
 
-class Graphicsmagick < Imagemagick
+# This formula used to drive from ImageMagick, but has diverged.
+
+def ghostscript_fonts?
+  File.directory? "#{HOMEBREW_PREFIX}/share/ghostscript/fonts"
+end
+
+def ghostscript_srsly?
+  ARGV.include? '--with-ghostscript'
+end
+
+def x11?
+  # I used this file because old Xcode seems to lack it, and its that old
+  # Xcode that loads of people seem to have installed still
+  File.file? '/usr/X11/include/ft2build.h'
+end
+
+class Graphicsmagick <Formula
   url 'http://downloads.sourceforge.net/project/graphicsmagick/graphicsmagick/1.3.12/GraphicsMagick-1.3.12.tar.bz2'
   homepage 'http://www.graphicsmagick.org/'
   md5 '55182f371f82d5f9367bce04e59bbf25'
 
-  def deps
-    # well this was an unexpected consequence of the DSL syntax, the dependencies
-    # aren't inherited
-    @deps ||= Formula.factory('imagemagick').deps
+  depends_on 'jpeg'
+  depends_on 'libwmf' => :optional if x11?
+  depends_on 'libtiff' => :optional
+  depends_on 'little-cms' => :optional
+  depends_on 'jasper' => :optional
+  depends_on 'ghostscript' => :recommended if ghostscript_srsly? and x11?
+  depends_on 'libpng' unless x11?
+
+  def skip_clean? path
+    path.extname == '.la'
   end
 
   def install
-    ENV.libpng
     ENV.gcc_4_2
+    ENV.libpng
+    ENV.O3
 
-    fix_configure
+    # versioned stuff in main tree is pointless for us
+    inreplace 'configure', '${PACKAGE_NAME}-${PACKAGE_VERSION}', '${PACKAGE_NAME}'
 
-    system "./configure", *configure_args
+    args = [ "--prefix=#{prefix}",
+             "--disable-dependency-tracking",
+             "--enable-shared",
+             "--disable-static",
+             "--with-modules",
+             "--without-magick-plus-plus" ]
+
+     args << "--disable-openmp" if MACOS_VERSION < 10.6   # libgomp unavailable
+     args << "--with-gslib" if ghostscript_srsly?
+     args << "--with-gs-font-dir=#{HOMEBREW_PREFIX}/share/ghostscript/fonts" \
+              unless ghostscript_fonts?
+
+    system "./configure", *args
     system "make install"
   end
+
+  def caveats
+    "You don't have X11 from the Xcode DMG installed. Consequently GraphicsMagick is less fully featured." unless x11?
+  end
 end