spice-gtk: add spice-protocol to devel depends

This is not added automatically, but is required.

srcpkgs/spice-gtk/template

@@ -1,7 +1,7 @@
 # Template file for 'spice-gtk'
 pkgname=spice-gtk
 version=0.37
-revision=3
+revision=4
 build_style=meson
 build_helper="gir"
 configure_args="-Dintrospection=$(vopt_if gir enabled disabled)
@@ -36,7 +36,8 @@ spice-gtk-devel_package() {
 	depends="gtk+3-devel pixman-devel libressl-devel opus-devel
 	 libva-devel libsasl-devel liblz4-devel usbredir-devel phodav-devel
 	 json-glib-devel gstreamer1-devel gst-plugins-base1-devel
-	 $(vopt_if gir libgirepository-devel) ${sourcepkg}-${version}_${revision}"
+	 spice-protocol $(vopt_if gir libgirepository-devel)
+	 ${sourcepkg}-${version}_${revision}"
 	short_desc+=" - development files"
 	pkg_install() {
 		vmove usr/include