GN: Add option to build with TSAN

runtime/BUILD.gn

 # Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 declare_args() {
   # Instead of using is_debug, we introduce a different flag for specifying a
   # Debug build of Dart so that clients can still use a Release build of Dart
   # while themselves doing a Debug build.
   dart_debug = false
 
@@ skipping 150 matching lines @@
       "-fno-rtti",
       "-fno-exceptions",
     ]
 
     if (dart_debug) {
       cflags += [ "-O1" ]
     } else {
       cflags += [ "-O3" ]
     }
 
+    ldflags = []
     if (defined(is_asan) && is_asan) {
-      ldflags = [ "-fsanitize=address" ]
+      ldflags += [ "-fsanitize=address" ]
+    }
+    if (defined(is_msan) && is_msan) {
+      ldflags += [ "-fsanitize=memory" ]
+    }
+    if (defined(is_tsan) && is_tsan) {
+      ldflags += [ "-fsanitize=thread" ]
     }
   }
 }
 
 template("libdart_library") {
   extra_configs = []
   if (defined(invoker.extra_configs)) {
     extra_configs += invoker.extra_configs
   }
   extra_deps = []
@@ skipping 111 matching lines @@
     "third_party/double-conversion/src:libdouble_conversion",
     "vm:libdart_lib",
     "vm:libdart_lib_nosnapshot",
     "vm:libdart_vm",
     "vm:libdart_vm_nosnapshot",
   ]
   sources = [
     "vm/libdart_dependency_helper.cc",
   ]
 }