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/qsynth/template

@@ -3,7 +3,7 @@ pkgname=qsynth
 version=0.3.6
 homepage="http://qsynth.sourceforge.net"
 distfiles="${SOURCEFORGE_SITE}/$pkgname/$pkgname-$version.tar.gz"
-build_style=gnu_configure
+build_style=gnu-configure
 short_desc="Qt GUI Interface for FluidSynth"
 maintainer="davehome <davehome@redthumb.info.tm>"
 license="GPL-2"