Win32: Fix key names not matching other platforms

This brings printable key names more in line with the results provided
on other platforms.

Fixes #943.

src/win32_platform.h

@@ -250,9 +250,9 @@ typedef struct _GLFWlibraryWin32
     DWORD               foregroundLockTimeout;
     int                 acquiredMonitorCount;
     char*               clipboardString;
-    char                keyName[64];
     short int           keycodes[512];
     short int           scancodes[GLFW_KEY_LAST + 1];
+    char                keynames[GLFW_KEY_LAST + 1][5];
     // Where to place the cursor when re-enabled
     double              restoreCursorPosX, restoreCursorPosY;
     // The window whose disabled cursor mode is active
@@ -353,6 +353,7 @@ void _glfwUnregisterWindowClassWin32(void);
 WCHAR* _glfwCreateWideStringFromUTF8Win32(const char* source);
 char* _glfwCreateUTF8FromWideStringWin32(const WCHAR* source);
 void _glfwInputErrorWin32(int error, const char* description);
+void _glfwUpdateKeyNamesWin32(void);
 
 void _glfwInitTimerWin32(void);