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/apache/template

@@ -3,7 +3,7 @@ pkgname=apache
 version=2.2.21
 wrksrc=httpd-${version}
 distfiles="http://www.apache.org/dist/httpd/httpd-${version}.tar.bz2"
-build_style=gnu_configure
+build_style=gnu-configure
 configure_args="--prefix= --enable-pie --enable-modules=all
 --enable-mods-shared=all --enable-authn-dbm --enable-authn-anon
 --enable-authn-dbd --enable-authn-alias --enable-authz-dbm