x11-toolkits/gtk40: enable VULKAN by default

Vulkan has to be explicitly enabled at runtime e.g.,

  $ GSK_RENDERER=vulkan gtk4-demo

PR:		256333
Inspired by:	Alpine, AOSC, Arch, Ataraxia, Debian, KaOS, Mageia, Nix, openmamba, OpenMandriva, openSUSE, Pisi, Void
Approved by:	tcberner

x11-toolkits/gtk40/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	gtk
 PORTVERSION=	4.2.1
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	x11-toolkits
 MASTER_SITES=	GNOME
 PKGNAMESUFFIX=	4
@@ -50,7 +50,7 @@ LDFLAGS+=	-fuse-ld=lld
 
 OPTIONS_DEFINE=	CUPS CLOUDPRINT COLORD DEBUG BROADWAY FFMPEG \
 		GSTREAMER VULKAN WAYLAND X11
-OPTIONS_DEFAULT=CUPS COLORD BROADWAY WAYLAND X11
+OPTIONS_DEFAULT=CUPS COLORD BROADWAY VULKAN WAYLAND X11
 OPTIONS_SUB=	yes
 
 BROADWAY_DESC=	Enable GDK Broadway backend for showing GTK+ in the webbrowser using HTML5 and web sockets.