Added formula for GDAL-GRASS plugin

Once GRASS has been installed, this plugin may be used to extend the
capabilities of the GDAL library so that its tools may be used to retrieve data
stored in GRASS raster and vector formats.

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

Formula/gdal-grass.rb

@@ -0,0 +1,35 @@
+require 'formula'
+
+class GdalGrass <Formula
+  homepage 'http://www.gdal.org'
+  url 'http://download.osgeo.org/gdal/gdal-grass-1.4.3.tar.gz'
+  md5 '2bfb7640e03b4d9d012f1a5d62c0351d'
+
+  depends_on 'gdal'
+  depends_on 'grass'
+
+  def install
+    grass = Formula.factory('grass')
+
+    system "./configure", "--prefix=#{prefix}",
+                          "--disable-debug",
+                          "--disable-dependency-tracking",
+                          "--with-gdal=#{HOMEBREW_PREFIX}/bin/gdal-config",
+                          "--with-grass=#{grass.prefix}/grass-#{grass.version}",
+                          "--with-autoload=#{lib}/gdalplugins"
+
+    inreplace "Makefile", 'mkdir', 'mkdir -p'
+
+    system "make install"
+  end
+
+  def caveats
+    caveats = <<-EOS
+This formula provides a plugin that allows GDAL and OGR to access geospatial
+data stored using the GRASS vector and raster formats. In order to use the
+plugin, you will need to add the following path to the GDAL_DRIVER_PATH
+enviroment variable:
+    #{HOMEBREW_PREFIX}/lib/gdalplugins
+    EOS
+  end
+end