cppcheck: Update to 1.51

Also added options:

-Updated tarball and md5 for 1.51
-Added an option to build the cppcheck qt-gui
-Added an option to build without rules, in which case there's no dependency on pcre
-Added caveats explaining how to link the cppcheck-gui.app in case --with-gui is used for install

Closes Homebrew/homebrew#8683.

Signed-off-by: Charlie Sharpsteen <source@sharpsteen.net>

Formula/cppcheck.rb

@@ -1,20 +1,56 @@
 require 'formula'
 
 class Cppcheck < Formula
-  url 'http://downloads.sourceforge.net/project/cppcheck/cppcheck/1.50/cppcheck-1.50.tar.bz2'
+  url 'http://downloads.sourceforge.net/project/cppcheck/cppcheck/1.51/cppcheck-1.51.tar.bz2'
   homepage 'http://sourceforge.net/apps/mediawiki/cppcheck/index.php?title=Main_Page'
-  md5 '79ef3898b246ba9c143155d5ad23dbd1'
+  md5 '8349ab90472801b9d377cfabf846ca28'
   head 'https://github.com/danmar/cppcheck.git'
 
-  depends_on 'pcre'
+  depends_on 'pcre' unless ARGV.include? '--no-rules'
+  depends_on 'qt' if ARGV.include? '--with-gui'
+
+  def options
+    [
+      ['--no-rules', "Build without rules (no pcre dependency)"],
+      ['--with-gui', "Build the cppcheck gui."]
+    ]
+  end
 
   # Do not strip binaries, or else it fails to run.
   skip_clean :all
 
   def install
     # Pass to make variables.
-    system "make"
+    if ARGV.include? '--no-rules'
+      system "make", "HAVE_RULES=no"
+    else
+      system "make"
+    end
+
     system "make", "DESTDIR=#{prefix}", "BIN=#{bin}", "install"
+
+    if ARGV.include? '--with-gui'
+      Dir.chdir "gui"
+      if ARGV.include? '--no-rules'
+        system "qmake", "HAVE_RULES=no"
+      else
+        system "qmake"
+      end
+
+      system "make"
+      bin.install "cppcheck-gui.app"
+    end
     # Man pages aren't installed, they require docbook schemas which I don't know how to install.
   end
+  def caveats; <<-EOS.undent
+    --with-gui installs cppcheck-gui.app in:
+      #{bin}
+
+    To link the application to a normal Mac OS X location:
+        brew linkapps
+    or:
+        ln -s #{bin}/cppcheck-gui.app /Applications
+    EOS
+  end
+
 end