diff --git a/www-client/seamonkey/seamonkey-2.53.13.ebuild b/www-client/seamonkey/seamonkey-2.53.13.ebuild
index d61c8f33b22f1..7f598f4500d48 100644
--- a/www-client/seamonkey/seamonkey-2.53.13.ebuild
+++ b/www-client/seamonkey/seamonkey-2.53.13.ebuild
@@ -179,6 +179,9 @@ src_unpack() {
 }
 
 src_prepare() {
+	# Hotfix for bug: 869143
+	sed -e '/^#include <stddef.h>/a #include <utility>' -i mfbt/tests/TestUniquePtr.cpp || die
+
 	# Apply our patches
 	eapply "${WORKDIR}"/gentoo-${PN}-patches-${PV}/${PN}