diff --git a/b2g/confvars.sh b/b2g/confvars.sh
index 31a11c6f7e6..2367e7e7a02 100644
--- a/b2g/confvars.sh
+++ b/b2g/confvars.sh
@@ -26,6 +26,7 @@ MOZ_WEBSMS_BACKEND=1
 MOZ_DISABLE_CRYPTOLEGACY=1
 MOZ_APP_STATIC_INI=1
 NSS_NO_LIBPKIX=1
+MOZ_DISABLE_EXPORT_JS=1
 
 if test "$OS_TARGET" = "Android"; then
 MOZ_CAPTURE=1
diff --git a/mobile/android/confvars.sh b/mobile/android/confvars.sh
index 72ada1cee9c..c5916294333 100644
--- a/mobile/android/confvars.sh
+++ b/mobile/android/confvars.sh
@@ -33,6 +33,7 @@ MOZ_RAW=1
 MOZ_PLACES=
 MOZ_SOCIAL=
 MOZ_ANDROID_HISTORY=1
+MOZ_DISABLE_EXPORT_JS=1
 
 # Needed for building our components as part of libxul
 MOZ_APP_COMPONENT_LIBS="browsercomps"