[gthumb] meson: try webkit2gtk-3.0 if webkit2gtk-4.0 is not found

[Paolo Bacchilega <paobac src gnome org>]

commit c0fe934961a0bd5752dba1d7697029823268c0bf
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Mon Oct 23 10:52:11 2017 +0200

    meson: try webkit2gtk-3.0 if webkit2gtk-4.0 is not found

 meson.build |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/meson.build b/meson.build
index def8f44..88503ed 100644
--- a/meson.build
+++ b/meson.build
@@ -176,6 +176,9 @@ if get_option('webservices')
   libsoup_dep = dependency('libsoup-2.4', version : libsoup_version, required : false)
   libjson_glib_dep = dependency('json-glib-1.0', version : libjson_glib_version, required : false)
   webkit2_dep = dependency('webkit2gtk-4.0', version : webkit2_version, required : false)
+  if not webkit2_dep.found()
+    webkit2_dep = dependency('webkit2gtk-3.0', version : webkit2_version, required : false)
+  endif
   with_webservices = libsoup_dep.found() and libjson_glib_dep.found() and webkit2_dep.found()
   
   if with_webservices and get_option('libsecret')