Sanitizers: Roll in 16 months of libcxx and libcxxabi changes.

third_party/libc++/BUILD.gn

Index: third_party/libc++/BUILD.gn
diff --git a/third_party/libc++/BUILD.gn b/third_party/libc++/BUILD.gn
index a3c4ec26329368c29cc24c96bf8b9f8f8115483b..3c0aafc4ebb9b493b65a9770eea2cd52fce38547 100644
--- a/third_party/libc++/BUILD.gn
+++ b/third_party/libc++/BUILD.gn
@@ -30,6 +30,7 @@ shared_library("libc++") {
     "trunk/src/condition_variable.cpp",
     "trunk/src/debug.cpp",
     "trunk/src/exception.cpp",
+    "trunk/src/functional.cpp",
     "trunk/src/future.cpp",
     "trunk/src/hash.cpp",
     "trunk/src/ios.cpp",
@@ -50,6 +51,7 @@ shared_library("libc++") {
     "trunk/src/typeinfo.cpp",
     "trunk/src/utility.cpp",
     "trunk/src/valarray.cpp",
+    "trunk/src/variant.cpp",
   ]
   configs -= [
     "//build/config/compiler:chromium_code",
@@ -64,6 +66,7 @@ shared_library("libc++") {
     "//build/config/gcc:symbol_visibility_default",
     "//build/config/sanitizers:sanitizer_options_link_helper",
   ]
+  defines = [ "_LIBCPP_BUILDING_LIBRARY" ]
 
   ldflags = [ "-nodefaultlibs" ]