--- /var/portage/tree/games-emulation/dosbox/dosbox-0.70.ebuild	2007-03-03 21:46:17.000000000 +0100
+++ games-emulation/dosbox/dosbox-0.70.ebuild	2007-03-04 02:34:01.899981864 +0100
@@ -21,6 +21,14 @@
 	media-libs/sdl-net
 	media-libs/sdl-sound"
 
+pkg_setup() {
+	if use alsa && ! built_with_use --missing true media-libs/alsa-lib midi; then
+		eerror "To be able to build dosbox with ALSA support you need"
+		eerror "to have built media-libs/alsa-lib with midi USE flag."
+		die "Missing midi USE flag on media-libs/alsa-lib"
+	fi
+}
+
 src_compile() {
 	local myconf=