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/libldap/template

@@ -3,7 +3,7 @@ pkgname=libldap
 version=2.4.24
 wrksrc="openldap-${version}"
 distfiles="ftp://ftp.openldap.org/pub/OpenLDAP/openldap-release/openldap-$version.tgz"
-build_style=gnu_configure
+build_style=gnu-configure
 configure_args="--enable-dynamic --enable-proctitle
 --enable-ipv6 --enable-local --with-cyrus-sasl --with-threads --with-tls
 --enable-syslog --disable-slapd"