Switch to clang-r399163.

Bug: http://b/155835175
Bug: http://b/151457797
Bug: http://b/165945989
Test: m with aosp_blueline
Change-Id: Id2c2932ccbc34fcbb19cd0b4da0d66ea92cc099a
diff --git a/cc/config/x86_windows_host.go b/cc/config/x86_windows_host.go
index b5b5553..b77df79 100644
--- a/cc/config/x86_windows_host.go
+++ b/cc/config/x86_windows_host.go
@@ -39,6 +39,9 @@
 		// Get 64-bit off_t and related functions.
 		"-D_FILE_OFFSET_BITS=64",
 
+		// Don't adjust the layout of bitfields like msvc does.
+		"-mno-ms-bitfields",
+
 		"--sysroot ${WindowsGccRoot}/${WindowsGccTriple}",
 	}
 	windowsClangCflags = append(ClangFilterUnknownCflags(windowsCflags), []string{}...)