[gnome-documents] build, lokview: Bump minimum GJS requirement to 1.48.0

[Debarshi Ray <debarshir src gnome org>]

commit 13da84ec220619e0bb92658d1b4c5f50e4542a16
Author: Debarshi Ray <debarshir gnome org>
Date:   Tue Apr 4 20:08:51 2017 +0200

    build, lokview: Bump minimum GJS requirement to 1.48.0
    
    ... and adjust the LOKDocView detection accordingly. A newer GJS is
    needed for Map.forEach.
    
    Fallout from 0068808c1a086efb36db1346ad59bc250f982d00
    
    https://bugzilla.gnome.org/show_bug.cgi?id=769088

 configure.ac   |    3 ++-
 src/lokview.js |    4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index db0b9f6..41d5bcf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -52,6 +52,7 @@ AC_SUBST(LIBM)
 EVINCE_MIN_VERSION=3.13.3
 WEBKITGTK_MIN_VERSION=2.6.0
 GLIB_MIN_VERSION=2.39.3
+GJS_MIN_VERSION=1.48.0
 GTK_MIN_VERSION=3.22.10
 GOBJECT_INTROSPECTION_MIN_VERSION=1.31.6
 GDATA_MIN_VERSION=0.13.3
@@ -76,7 +77,7 @@ PKG_CHECK_MODULES(DOCUMENTS,
                   evince-document-3.0 >= $EVINCE_MIN_VERSION
                   evince-view-3.0 >= $EVINCE_MIN_VERSION
                   webkit2gtk-4.0 >= $WEBKITGTK_MIN_VERSION
-                  gjs-1.0
+                  gjs-1.0 >= $GJS_MIN_VERSION
                   glib-2.0 >= $GLIB_MIN_VERSION
                   gobject-introspection-1.0 >= $GOBJECT_INTROSPECTION_MIN_VERSION
                   gtk+-3.0 >= $GTK_MIN_VERSION
diff --git a/src/lokview.js b/src/lokview.js
index 988db96..31ac7e6 100644
--- a/src/lokview.js
+++ b/src/lokview.js
@@ -19,8 +19,10 @@
  *
  */
 
+let LOKDocView;
+
 try {
-    const LOKDocView = imports.gi.LOKDocView;
+    LOKDocView = imports.gi.LOKDocView;
 } catch(e) {
     // LOKDocView will be undefined, and we'll
     // use this to warn when LO files can't be opened