Index: devel/boost-libs/Makefile
===================================================================
--- devel/boost-libs/Makefile	(revision 423562)
+++ devel/boost-libs/Makefile	(working copy)
@@ -37,6 +37,12 @@
 PLIST_SUB+=	COROUTINE="" CONTEXT="" LOCALE="" LOG=""
 .endif
 
+# fix for lang/gcc5
+.include <bsd.port.pre.mk>
+.if ${COMPILER_TYPE} == gcc
+CXXFLAGS += -std=gnu++11 -D_GLIBCXX_USE_C99=1 -include cmath
+.endif
+
 do-build:
 	@cd ${WRKSRC} && \
 		${SETENV} ${MAKE_ENV} ${BJAM} ${BJAM_ARGS} stage