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/xkeyboard-config.tmpl

@@ -1,8 +1,8 @@
 # Template build file for 'xkeyboard-config'.
 pkgname=xkeyboard-config
 version=1.4
-extract_sufx=".tar.bz2"
-url=http://xlibs.freedesktop.org/xkbdesc
+distfiles="
+http://xlibs.freedesktop.org/xkbdesc/$pkgname-$version@.tar.bz2"
 build_style=gnu_configure
 configure_args="--with-xkb-rules-symlink=xfree86,xorg
  --enable-compat-rules"