[Windows] Pass "/MD" and variants outside the "runtime_library" target

build/config/win/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/clang/clang.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/win/visual_studio_version.gni")
 import("//build/toolchain/toolchain.gni")
 
@@ skipping 175 matching lines @@
     "PSAPI_VERSION=1",
     "WIN32",
     "_SECURE_ATL",
   ]
 
   if (!use_vs_code_analysis) {
     # This is required for ATL to use XP-safe versions of its functions.
     # However it is prohibited when using /analyze
     defines += [ "_USING_V110_SDK71_" ]
   }
+}
 
+# Configures how the runtime library (CRT) is going to be used.
+# See https://msdn.microsoft.com/en-us/library/2kzt1wy3.aspx for a reference of
+# what each value does.
+config("crt") {

[brettw, 2016/09/28 17:22:02]

If we're going to be changing this, I think a better structure would be to call
this "default_crt" and have that conditionally reference a "static_crt" or a
"dynamic_crt" config based on that. This way your target code removes the
default and adds the dynamic one without hard-coding CRT flags.

(The dynamic and static CRT configs would have the debug/release logic inside
them, it seems like overkill to separate out this into separate configs.)

   if (is_component_build) {
     # Component mode: dynamic CRT. Since the library is shared, it requires
     # exceptions or will give errors about things not matching, so keep
     # exceptions on.
     if (is_debug) {
       cflags += [ "/MDd" ]
     } else {
       cflags += [ "/MD" ]
     }
   } else {
@@ skipping 189 matching lines @@
 
 # Internal stuff --------------------------------------------------------------
 
 # Config used by the MIDL template to disable warnings.
 config("midl_warnings") {
   if (is_clang) {
     # MIDL generates code like "#endif !_MIDL_USE_GUIDDEF_".
     cflags = [ "-Wno-extra-tokens" ]
   }
 }