Major changes to support multiple distfiles in templates.

Each template now needs to use $distfiles that accepts the full
URL to download the distfile and old $extract_sufx is now merged
on it, but this must be separated by the '@' character. Example:

distfiles="http://www.foo.org/blah-6.2@.tar.gz
http://www.foo.org/blob-1.0@.tar.bz2"

If distfiles contains multiple files defined, $wrksrc is now
mandatory.

--HG--
extra : convert_revision : 1c3fa35f148af8323ce3cbcf5732104960de6bc4

templates/ruby.tmpl

@@ -1,8 +1,8 @@
 # Template build file for 'ruby'.
 pkgname=ruby
 version=1.8.7-p72
-extract_sufx=".tar.bz2"
-url=ftp://ftp.ruby-lang.org/pub/ruby/1.8
+distfiles="
+ftp://ftp.ruby-lang.org/pub/ruby/1.8/$pkgname-$version@.tar.bz2"
 build_style=gnu_configure
 # Override --exec-prefix to install it into the correct location.
 configure_args="--enable-pthread --enable-shared