[vte/ricotz/vala] vala: Support building bindings for vte-2.91-gtk4

[Rico Tzschichholz <ricotz src gnome org>]

commit 6e879476200dd5cf5acc5be88caabeeb26d204c4
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat Mar 5 08:49:17 2022 +0100

    vala: Support building bindings for vte-2.91-gtk4
    
    Fixes https://gitlab.gnome.org/GNOME/vte/-/issues/2546

 bindings/meson.build      |  2 +-
 bindings/vala/meson.build | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)
---
diff --git a/bindings/meson.build b/bindings/meson.build
index 626e4679..2fc8dd60 100644
--- a/bindings/meson.build
+++ b/bindings/meson.build
@@ -22,6 +22,6 @@ if get_option('gir') and (get_option('gtk3') or get_option('gtk4'))
   subdir('gir')
 endif
 
-if get_option('vapi') and get_option('gtk3')
+if get_option('vapi') and (get_option('gtk3') or get_option('gtk4'))
   subdir('vala')
 endif
diff --git a/bindings/vala/meson.build b/bindings/vala/meson.build
index ec1ddf0b..415f561c 100644
--- a/bindings/vala/meson.build
+++ b/bindings/vala/meson.build
@@ -15,7 +15,6 @@
 # along with this library.  If not, see <https://www.gnu.org/licenses/>.
 
 assert(get_option('gir'), 'gir is required for vala support')
-assert(get_option('gtk3'), 'vala support only available for gtk3')
 
 add_languages('vala', required: true)
 
@@ -24,6 +23,24 @@ assert(valac.version().version_compare('>= 0.24.0'), 'vala >= 0.24 required')
 
 posix_dep = valac.find_library('posix')
 
+if get_option('gtk4')
+libvte_gtk4_vapi_deps = [
+  'gio-2.0',
+  'glib-2.0',
+  'graphene-1.0',
+  'pango',
+  'gtk4',
+]
+
+libvte_gtk4_vapi_dep = gnome.generate_vapi(
+  vte_gtk4_api_name,
+  sources: libvte_gtk4_gir[0],
+  packages: libvte_gtk4_vapi_deps,
+  install: true,
+)
+endif
+
+if get_option('gtk3')
 libvte_gtk3_vapi_deps = [
   'gio-2.0',
   'glib-2.0',
@@ -98,3 +115,4 @@ vapp = executable(
   vala_args: vapp_valaflags,
   install: false,
 )
+endif