--- www/chromium/Makefile	(revision 427613)
+++ www/chromium/Makefile	(working copy)
@@ -93,7 +93,7 @@ 
 		use_system_sqlite=false   # chrome has additional patches
 # TODO: investigate building with these options:
 # use_system_icu use_system_harfbuzz use_system_minigbm
-GN_BOOTSTRAP_FLAGS=	--no-clean --no-rebuild
+GN_BOOTSTRAP_FLAGS=	--no-clean --no-rebuild -v
 
 # FreeBSD Chromium Api Key
 # Set up Google API keys, see http://www.chromium.org/developers/how-tos/api-keys .
@@ -187,7 +187,14 @@ 
 		CPLUS_INCLUDE_PATH=${LOCALBASE}/include
 GN_ARGS+=	is_clang=true
 EXTRA_PATCHES+=	${FILESDIR}/extra-patch-clang
+.if ${OSVERSION} < 1200017
+.warning Using _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
+EXTRA_PATCHES+=	${FILESDIR}/extra-patch-libc++-old
+.else
+.warning Using _LIBCPP_ABI_UNSTABLE
+EXTRA_PATCHES+=	${FILESDIR}/extra-patch-libc++-new
 .endif
+.endif
 
 .if ${OPSYS} == FreeBSD && ${OSVERSION} < 1002000
 BUILD_DEPENDS+=	${LOCALBASE}/lib/c++/libstdc++.so:devel/libc++
--- www/chromium/files/extra-patch-libc++-new	(nonexistent)
+++ www/chromium/files/extra-patch-libc++-new	(working copy)
@@ -0,0 +1,14 @@ 
+--- services/ui/ws/BUILD.gn.orig	2016-10-06 04:02:24.000000000 +0300
++++ services/ui/ws/BUILD.gn	2016-10-19 11:13:25.102806000 +0300
+@@ -103,6 +103,11 @@
+     "window_tree_host_factory.h",
+   ]
+ 
++  # Work around base r261801
++  if (is_bsd) {
++    defines = ["_LIBCPP_ABI_UNSTABLE=1"]
++  }
++
+   deps = [
+     # TODO(sad): Temporary, until the GPU process is split out of ws.
+     "//services/ui/gpu",
--- www/chromium/files/extra-patch-libc++-old	(nonexistent)
+++ www/chromium/files/extra-patch-libc++-old	(working copy)
@@ -0,0 +1,14 @@ 
+--- services/ui/ws/BUILD.gn.orig	2016-10-06 04:02:24.000000000 +0300
++++ services/ui/ws/BUILD.gn	2016-10-19 11:13:25.102806000 +0300
+@@ -103,6 +103,11 @@
+     "window_tree_host_factory.h",
+   ]
+ 
++  # Work around base r261801
++  if (is_bsd) {
++    defines = ["_LIBCPP_TRIVIAL_PAIR_COPY_CTOR=1"]
++  }
++
+   deps = [
+     # TODO(sad): Temporary, until the GPU process is split out of ws.
+     "//services/ui/gpu",
--- www/chromium/files/patch-services_ui_ws_BUILD.gn	(revision 427613)
+++ www/chromium/files/patch-services_ui_ws_BUILD.gn	(nonexistent)
@@ -1,14 +0,0 @@ 
---- services/ui/ws/BUILD.gn.orig	2016-10-06 04:02:24.000000000 +0300
-+++ services/ui/ws/BUILD.gn	2016-10-19 11:13:25.102806000 +0300
-@@ -103,6 +103,11 @@
-     "window_tree_host_factory.h",
-   ]
- 
-+  # Work around base r261801
-+  if (is_bsd) {
-+    defines = ["_LIBCPP_TRIVIAL_PAIR_COPY_CTOR=1"]
-+  }
-+
-   deps = [
-     # TODO(sad): Temporary, until the GPU process is split out of ws.
-     "//services/ui/gpu",