[gnome-sdk-images] Add another hack to try to fix WebKit

[Michael Catanzaro <mcatanzaro src gnome org>]

commit cb1b2936f007c3ffba44574860c36ee577c7cb58
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Sun Jan 14 15:44:22 2018 -0600

    Add another hack to try to fix WebKit

 org.gnome.Sdk.json.in |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/org.gnome.Sdk.json.in b/org.gnome.Sdk.json.in
index 6d492fa..187f9ce 100644
--- a/org.gnome.Sdk.json.in
+++ b/org.gnome.Sdk.json.in
@@ -793,7 +793,8 @@
                 "-DINCLUDE_INSTALL_DIR:PATH=/usr/include",
                 "-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON",
                 "-DENABLE_MINIBROWSER=ON",
-                "-DUSE_UPOWER=OFF" /* FIXME: Timers will not be throttled on low power. */
+                "-DUSE_UPOWER=OFF" /* FIXME: Timers will not be throttled on low power. */,
+                "-DDEVELOPER_MODE=ON" /* HACK: https://bugs.webkit.org/show_bug.cgi?id=181438 */
             ],
             "sources": [
                 {