Some fixes for MinGW

* Rename Windows.h uses to windows.h
  * Comment out structured exception handling usage

Makes MinGW happier. Mostly the same as previous work by
Nicolas Dufresne <nicolas.dufresne@collabora.com>, with the exception
that we now don't try to invoke RaiseException which would fail in MinGW
as it raises a Windows structured exception.

webrtc/rtc_base/platform_thread_types.cc

@@ -99,11 +99,13 @@ void SetCurrentThreadName(const char* name) {
 
 #pragma warning(push)
 #pragma warning(disable : 6320 6322)
+#ifndef __MINGW32__
   __try {
     ::RaiseException(0x406D1388, 0, sizeof(threadname_info) / sizeof(ULONG_PTR),
                      reinterpret_cast<ULONG_PTR*>(&threadname_info));
   } __except (EXCEPTION_EXECUTE_HANDLER) {  // NOLINT
   }
+#endif
 #pragma warning(pop)
 #elif defined(WEBRTC_LINUX) || defined(WEBRTC_ANDROID)
   prctl(PR_SET_NAME, reinterpret_cast<unsigned long>(name));  // NOLINT

webrtc/rtc_base/synchronization/rw_lock_win.h

@@ -11,7 +11,7 @@
 #ifndef RTC_BASE_SYNCHRONIZATION_RW_LOCK_WIN_H_
 #define RTC_BASE_SYNCHRONIZATION_RW_LOCK_WIN_H_
 
-#include <Windows.h>
+#include <windows.h>
 
 #include "rtc_base/synchronization/rw_lock_wrapper.h"
 

webrtc/rtc_base/system/file_wrapper.cc

@@ -14,7 +14,7 @@
 #include <cerrno>
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #else
 #include <string.h>
 #endif