Update build_style for all templates.

- There's no need to set build_style for custom-install (default).
- gnu_{configure,makefile} renamed to gnu-{configure,makefile}.

srcpkgs/Thunar/template

@@ -2,7 +2,7 @@
 pkgname=Thunar
 version=1.2.2
 distfiles="http://archive.xfce.org/src/xfce/thunar/1.2/Thunar-$version.tar.bz2"
-build_style=gnu_configure
+build_style=gnu-configure
 configure_args="--enable-gio-unix --enable-dbus --enable-gudev --enable-exif
 --enable-pcre --enable-notifications"
 short_desc="Thunar File Manager"