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

build/config/win/BUILD.gn

Index: build/config/win/BUILD.gn
diff --git a/build/config/win/BUILD.gn b/build/config/win/BUILD.gn
index b437516d6639ba7566e01db5ad14361f59fb2444..b48c52a002096ee5c80198c0497f8be114b808ab 100644
--- a/build/config/win/BUILD.gn
+++ b/build/config/win/BUILD.gn
@@ -193,7 +193,12 @@ config("runtime_library") {
     # 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