diff --git a/databases/percona57-server/Makefile b/databases/percona57-server/Makefile
index 9d7e78df4212..5227b70edb57 100644
--- a/databases/percona57-server/Makefile
+++ b/databases/percona57-server/Makefile
@@ -152,6 +152,8 @@ post-patch:
 	# issue 220865: MySQL developers forgot that FreeBSD != Linux
 	@${REINPLACE_CMD} -e 's|%%FREEBSD_LOCAL_LIB%%|${LOCALBASE}/lib|g' \
 	${WRKSRC}/configure.cmake
+	@${REINPLACE_CMD} -e 's|__clang__|__undefined__|g' \
+	    ${WRKDIR}/boost_1_59_0/boost/atomic/detail/ops_gcc_x86_dcas.hpp
 
 .include <bsd.port.pre.mk>