Allow disabling JIT for hardened.

Author: Magnus Granberg <zorry@gentoo.org>
Gentoo-bug: 562396

--- a/Tools/qmake/mkspecs/features/features.pri
+++ b/Tools/qmake/mkspecs/features/features.pri
@@ -70,6 +70,7 @@ FEATURE_DEFAULTS = \
     ENABLE_INPUT_TYPE_WEEK=0 \
     ENABLE_INSPECTOR=1 \
     ENABLE_INSPECTOR_SERVER=1 \
+    ENABLE_JIT=0 \
     ENABLE_JAVASCRIPT_DEBUGGER=1 \
     ENABLE_LEGACY_CSS_VENDOR_PREFIXES=0 \
     ENABLE_LEGACY_NOTIFICATIONS=1 \