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/freetype2.tmpl

@@ -1,9 +1,9 @@
 # Template build file for 'freetype2'.
 pkgname=freetype2
 version=2.3.7
-extract_sufx=".tar.bz2"
-distfiles="freetype-$version"
-url=http://download.savannah.gnu.org/releases/freetype
+wrksrc="freetype-$version"
+distfiles="
+http://download.savannah.gnu.org/releases/freetype/freetype-$version@.tar.bz2"
 build_style=gnu_configure
 make_cmd="$XBPS_MASTERDIR/bin/gmake"
 configure_env="GNUMAKE=$make_cmd"