diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 964bb909..035b57a6 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -22,7 +22,7 @@ if (_GLFW_COCOA)
                                 nsgl_context.m egl_context.c osmesa_context.c)
 elseif (_GLFW_WIN32)
     target_compile_definitions(glfw PRIVATE _GLFW_WIN32)
-    target_sources(glfw PRIVATE win32_platform.h win32_joystick.h
+    target_sources(glfw PRIVATE win32_platform.h win32_joystick.h win32_thread.h
                                 win32_init.c win32_joystick.c win32_monitor.c
                                 win32_time.c win32_thread.c win32_window.c
                                 wgl_context.c egl_context.c osmesa_context.c)
diff --git a/src/win32_platform.h b/src/win32_platform.h
index a258c355..a33e4e4b 100644
--- a/src/win32_platform.h
+++ b/src/win32_platform.h
@@ -356,6 +356,7 @@ typedef struct VkWin32SurfaceCreateInfoKHR
 typedef VkResult (APIENTRY *PFN_vkCreateWin32SurfaceKHR)(VkInstance,const VkWin32SurfaceCreateInfoKHR*,const VkAllocationCallbacks*,VkSurfaceKHR*);
 typedef VkBool32 (APIENTRY *PFN_vkGetPhysicalDeviceWin32PresentationSupportKHR)(VkPhysicalDevice,uint32_t);
 
+#include "win32_thread.h"
 #include "win32_joystick.h"
 
 #if !defined(_GLFW_WNDCLASSNAME)
@@ -367,8 +368,6 @@ typedef VkBool32 (APIENTRY *PFN_vkGetPhysicalDeviceWin32PresentationSupportKHR)(
 #define _GLFW_PLATFORM_LIBRARY_TIMER_STATE  _GLFWtimerWin32   win32
 #define _GLFW_PLATFORM_MONITOR_STATE        _GLFWmonitorWin32 win32
 #define _GLFW_PLATFORM_CURSOR_STATE         _GLFWcursorWin32  win32
-#define _GLFW_PLATFORM_TLS_STATE            _GLFWtlsWin32     win32
-#define _GLFW_PLATFORM_MUTEX_STATE          _GLFWmutexWin32   win32
 
 #define _GLFW_PLATFORM_CONTEXT_STATE            _GLFWcontextWGL wgl
 #define _GLFW_PLATFORM_LIBRARY_CONTEXT_STATE    _GLFWlibraryWGL wgl
@@ -536,22 +535,6 @@ typedef struct _GLFWtimerWin32
     uint64_t            frequency;
 } _GLFWtimerWin32;
 
-// Win32-specific thread local storage data
-//
-typedef struct _GLFWtlsWin32
-{
-    GLFWbool            allocated;
-    DWORD               index;
-} _GLFWtlsWin32;
-
-// Win32-specific mutex data
-//
-typedef struct _GLFWmutexWin32
-{
-    GLFWbool            allocated;
-    CRITICAL_SECTION    section;
-} _GLFWmutexWin32;
-
 
 GLFWbool _glfwRegisterWindowClassWin32(void);
 void _glfwUnregisterWindowClassWin32(void);
diff --git a/src/win32_thread.c b/src/win32_thread.c
index 53b34af2..35b8f99e 100644
--- a/src/win32_thread.c
+++ b/src/win32_thread.c
@@ -43,8 +43,7 @@ GLFWbool _glfwPlatformCreateTls(_GLFWtls* tls)
     tls->win32.index = TlsAlloc();
     if (tls->win32.index == TLS_OUT_OF_INDEXES)
     {
-        _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
-                             "Win32: Failed to allocate TLS index");
+        _glfwInputError(GLFW_PLATFORM_ERROR, "Win32: Failed to allocate TLS index");
         return GLFW_FALSE;
     }
 
diff --git a/src/win32_thread.h b/src/win32_thread.h
new file mode 100644
index 00000000..afc8f546
--- /dev/null
+++ b/src/win32_thread.h
@@ -0,0 +1,48 @@
+//========================================================================
+// GLFW 3.4 Win32 - www.glfw.org
+//------------------------------------------------------------------------
+// Copyright (c) 2002-2006 Marcus Geelnard
+// Copyright (c) 2006-2017 Camilla Löwy <elmindreda@glfw.org>
+//
+// This software is provided 'as-is', without any express or implied
+// warranty. In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+//    claim that you wrote the original software. If you use this software
+//    in a product, an acknowledgment in the product documentation would
+//    be appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such, and must not
+//    be misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source
+//    distribution.
+//
+//========================================================================
+
+#include <windows.h>
+
+#define _GLFW_PLATFORM_TLS_STATE            _GLFWtlsWin32     win32
+#define _GLFW_PLATFORM_MUTEX_STATE          _GLFWmutexWin32   win32
+
+// Win32-specific thread local storage data
+//
+typedef struct _GLFWtlsWin32
+{
+    GLFWbool            allocated;
+    DWORD               index;
+} _GLFWtlsWin32;
+
+// Win32-specific mutex data
+//
+typedef struct _GLFWmutexWin32
+{
+    GLFWbool            allocated;
+    CRITICAL_SECTION    section;
+} _GLFWmutexWin32;
+