[geary/wip/260-s390x-test-failure] Re-apply previous fix for s390x/pcc62

[Michael Gratton <mjog src gnome org>]

commit 719b3a197cd146aeab8e1a0ecd4d2f951a7959ae
Author: Michael Gratton <mike vee net>
Date:   Fri Feb 22 15:51:41 2019 +1100

    Re-apply previous fix for s390x/pcc62
    
    Bug 783883 fix had gone awol at some point.
    
    Fixes #260

 src/client/web-process/web-process-extension.vala | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/src/client/web-process/web-process-extension.vala 
b/src/client/web-process/web-process-extension.vala
index 1f478a6c..ac7723d7 100644
--- a/src/client/web-process/web-process-extension.vala
+++ b/src/client/web-process/web-process-extension.vala
@@ -87,7 +87,8 @@ public class GearyWebExtension : Object {
         bool should_load = false;
         WebKit.Frame frame = page.get_main_frame();
         // Explicit cast fixes build on s390x/ppc64. Bug 783882
-        unowned JS.GlobalContext context = frame.get_javascript_global_context();
+        unowned JS.GlobalContext context = (JS.GlobalContext)
+            frame.get_javascript_global_context();
         try {
             unowned JS.Value ret = execute_script(
                 context, "geary.allowRemoteImages", int.parse("__LINE__")
@@ -105,7 +106,8 @@ public class GearyWebExtension : Object {
     private void remote_image_load_blocked(WebKit.WebPage page) {
         WebKit.Frame frame = page.get_main_frame();
         // Explicit cast fixes build on s390x/ppc64. Bug 783882
-        unowned JS.GlobalContext context = frame.get_javascript_global_context();
+        unowned JS.GlobalContext context = (JS.GlobalContext)
+            frame.get_javascript_global_context();
         try {
             execute_script(
                 context, "geary.remoteImageLoadBlocked();", int.parse("__LINE__")
@@ -121,7 +123,8 @@ public class GearyWebExtension : Object {
     private void selection_changed(WebKit.WebPage page) {
         WebKit.Frame frame = page.get_main_frame();
         // Explicit cast fixes build on s390x/ppc64. Bug 783882
-        unowned JS.GlobalContext context = frame.get_javascript_global_context();
+        unowned JS.GlobalContext context = (JS.GlobalContext)
+            frame.get_javascript_global_context();
         try {
             execute_script(
                 context, "geary.selectionChanged();", int.parse("__LINE__")