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/apr-util/template

@@ -2,7 +2,7 @@
 pkgname=apr-util
 version=1.3.12
 distfiles="http://www.apache.org/dist/apr/${pkgname}-${version}.tar.bz2"
-build_style=gnu_configure
+build_style=gnu-configure
 configure_args="--with-pgsql --with-mysql --with-sqlite3 --with-ldap
 --with-berkeley-db --with-gdbm --with-apr=/usr --without-odbc
 --with-expat=/usr --without-oracle"