Optimize yasm even in debug builds

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 69867ecea3d0c95922cc314e53b3f4419b043978..940e55c6c28f033dea5235f08f78ca4df6b6c6a5 100644
--- a/build/config/win/BUILD.gn
+++ b/build/config/win/BUILD.gn
@@ -294,8 +294,21 @@ config("default_crt") {
   }
 }
 
+# Use this to force the debug CRT for when building perf-critical build tools
+# that need to be fully optimized even in debug builds, for those times when the
+# debug CRT is part of the bottleneck. This also avoids *implicitly* defining
+# _DEBUG.
+config("release_crt") {
+  if (is_component_build) {
+    cflags = [ "/MD" ]
+  } else {
+    cflags = [ "/MT" ]
+  }
+}
+
 config("dynamic_crt") {
   if (is_debug) {
+    # This pulls in the DLL debug CRT and defines _DEBUG
     cflags = [ "/MDd" ]
   } else {
     cflags = [ "/MD" ]
@@ -304,6 +317,7 @@ config("dynamic_crt") {
 
 config("static_crt") {
   if (is_debug) {
+    # This pulls in the static debug CRT and defines _DEBUG
     cflags = [ "/MTd" ]
   } else {
     cflags = [ "/MT" ]