Index: dist/libstdc++-v3/config/abi/pre/gnu.ver
===================================================================
RCS file: /cvsroot/src/external/gpl3/gcc/dist/libstdc++-v3/config/abi/pre/gnu.ver,v
retrieving revision 1.1.1.6
diff -p -u -u -r1.1.1.6 gnu.ver
--- dist/libstdc++-v3/config/abi/pre/gnu.ver	19 Jan 2019 10:14:13 -0000	1.1.1.6
+++ dist/libstdc++-v3/config/abi/pre/gnu.ver	28 Feb 2019 09:49:19 -0000
@@ -1007,7 +1007,8 @@ GLIBCXX_3.4 {
 #ifdef HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT
    # GLIBCXX_ABI compatibility only.
     # std::string
-    _ZNKSs11_M_disjunctEPKc;
+    # XXXMRG this causes dupe symbols on some netbsd ports
+    # _ZNKSs11_M_disjunctEPKc;
     _ZNKSs15_M_check_lengthE[jmy][jmy]PKc;
     _ZNSs4_Rep26_M_set_length_and_sharableE*;
     _ZNSs7_M_copyEPcPKc[jmy];
@@ -1015,7 +1016,8 @@ GLIBCXX_3.4 {
     _ZNSs9_M_assignEPc[jmy]c;
 
     # std::wstring
-    _ZNKSbIwSt11char_traitsIwESaIwEE11_M_disjunctEPKw;
+    # XXXMRG this causes dupe symbols on some netbsd ports
+    # _ZNKSbIwSt11char_traitsIwESaIwEE11_M_disjunctEPKw;
     _ZNKSbIwSt11char_traitsIwESaIwEE15_M_check_lengthE[jmy][jmy]PKc;
     _ZNSbIwSt11char_traitsIwESaIwEE4_Rep26_M_set_length_and_sharableE*;
     _ZNSbIwSt11char_traitsIwESaIwEE7_M_copyEPwPKw[jmy];
Index: lib/libstdc++-v3/Makefile
===================================================================
RCS file: /cvsroot/src/external/gpl3/gcc/lib/libstdc++-v3/Makefile,v
retrieving revision 1.44
diff -p -u -u -r1.44 Makefile
--- lib/libstdc++-v3/Makefile	27 Feb 2019 08:21:42 -0000	1.44
+++ lib/libstdc++-v3/Makefile	28 Feb 2019 09:49:19 -0000
@@ -18,15 +18,19 @@ LIBDPLIBS+=	m ${.CURDIR}/../../../../../
 COPTS.random.cc+=	${${ACTIVE_CC} == "clang":? -mrdrnd :}
 .endif
 
+DIST=		${GCCDIST}
+GNUVER=		${DIST}/libstdc++-v3/config/abi/pre/gnu.ver
 SYMBOLS=	libstdc++-symbols.ver
 .if ${MKPIC} != "no"
-${SYMBOLS}: Makefile
-	cat ${DIST}/libstdc++-v3/config/abi/pre/gnu.ver ${G_port_specific_symbol_files} | \
+${SYMBOLS}: Makefile ${GNUVER}
+	cat ${GNUVER} ${G_port_specific_symbol_files} | \
 	${TOOL_GREP} -E -v '^[     ]*#(#| |$$)' | \
-	${CXX} -I${DESTDIR}/usr/include/g++ -E -P -include ${.CURDIR}/arch/${LIBSTDCXX_MACHINE_ARCH}/c++config.h - > \
+	${CXX} -I${DESTDIR}/usr/include/g++ -E -P -include ${.CURDIR}/arch/${LIBSTDCXX_MACHINE_ARCH}/symver-config.h - > \
 	${.TARGET}.tmp && mv ${.TARGET}.tmp ${.TARGET} && rm -f ${.TARGET}.tmp
 
-CLEANFILES+=	${SYMBOLS}
+CLEANFILES+=	${SYMBOLS} ${SYMBOLS}.tmp
+
+DPADD+=		${SYMBOLS}
 
 .if ${MKPICLIB} != "no"
 libstdc++_pic.a:: ${SYMBOLS}