Add glfwGetKeyName

Fixes #464.

src/win32_window.c

@@ -1180,6 +1180,30 @@ void _glfwPlatformSetCursorMode(_GLFWwindow* window, int mode)
         SetCursor(NULL);
 }
 
+const char* _glfwPlatformGetKeyName(int key, int scancode)
+{
+    WCHAR name[16];
+
+    if (key != GLFW_KEY_UNKNOWN)
+        scancode = _glfw.win32.nativeKeys[key];
+
+    if (!_glfwIsPrintable(_glfw.win32.publicKeys[scancode]))
+        return NULL;
+
+    if (!GetKeyNameTextW(scancode << 16, name, sizeof(name) / sizeof(WCHAR)))
+        return NULL;
+
+    if (!WideCharToMultiByte(CP_UTF8, 0, name, -1,
+                             _glfw.win32.keyName,
+                             sizeof(_glfw.win32.keyName),
+                             NULL, NULL))
+    {
+        return NULL;
+    }
+
+    return _glfw.win32.keyName;
+}
+
 int _glfwPlatformCreateCursor(_GLFWcursor* cursor,
                               const GLFWimage* image,
                               int xhot, int yhot)