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/gucharmap/template

@@ -2,7 +2,7 @@
 pkgname=gucharmap
 version=3.2.1
 distfiles="${GNOME_SITE}/$pkgname/3.2/$pkgname-$version.tar.xz"
-build_style=gnu_configure
+build_style=gnu-configure
 configure_args="--disable-schemas-install --disable-scrollkeeper
 --with-gconf-schema-file-dir=/usr/share/gconf/schemas
 --enable-introspection"