ui/vnc: VNC requires PIXMAN

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>

meson.build

@@ -1560,7 +1560,11 @@ endif
 vnc = not_found
 jpeg = not_found
 sasl = not_found
-if get_option('vnc').allowed() and have_system
+if get_option('vnc') \
+             .disable_auto_if(not have_system) \
+             .require(pixman.found(),
+                      error_message: 'cannot enable VNC if pixman is not available') \
+             .allowed()
   vnc = declare_dependency() # dummy dependency
   jpeg = dependency('libjpeg', required: get_option('vnc_jpeg'),
                     method: 'pkg-config')

ui/meson.build

@@ -46,7 +46,7 @@ vnc_ss.add(files(
 ))
 vnc_ss.add(zlib, jpeg, gnutls)
 vnc_ss.add(when: sasl, if_true: files('vnc-auth-sasl.c'))
-system_ss.add_all(when: vnc, if_true: vnc_ss)
+system_ss.add_all(when: [vnc, pixman], if_true: vnc_ss)
 system_ss.add(when: vnc, if_false: files('vnc-stubs.c'))
 
 ui_modules = {}