Fix gettid() on Windows.

Accidentally had this all hidden by an #ifndef _WIN32 when I wrote it.

Bug: 19517541

(cherry picked from commit b3a36ca5ee79411c18984b85b224d9285b4468af)

Change-Id: Ifbd5d19e506e7313700e2e29a2dae5736e049844
diff --git a/include/cutils/threads.h b/include/cutils/threads.h
index 3133cdb..5727494 100644
--- a/include/cutils/threads.h
+++ b/include/cutils/threads.h
@@ -17,6 +17,14 @@
 #ifndef _LIBS_CUTILS_THREADS_H
 #define _LIBS_CUTILS_THREADS_H
 
+#include  <sys/types.h>
+
+#if !defined(_WIN32)
+#include <pthread.h>
+#else
+#include <windows.h>
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -29,10 +37,9 @@
 /***********************************************************************/
 /***********************************************************************/
 
-#if !defined(_WIN32)
+extern pid_t gettid();
 
-#include  <pthread.h>
-#include  <sys/types.h>
+#if !defined(_WIN32)
 
 typedef struct {
     pthread_mutex_t   lock;
@@ -40,14 +47,10 @@
     pthread_key_t     tls;
 } thread_store_t;
 
-extern pid_t gettid();
-
 #define  THREAD_STORE_INITIALIZER  { PTHREAD_MUTEX_INITIALIZER, 0, 0 }
 
 #else // !defined(_WIN32)
 
-#include <windows.h>
-
 typedef struct {
     int               lock_init;
     int               has_tls;