Workaround for glfw keyboard issue on linux.

Fixed issue #10

Demo/platform/port_glfw.cpp

@@ -224,10 +224,15 @@ static void key_callback(GLFWwindow *window, int key, int scancode, int action,
 		key_super = down;
 		break;
 	default:
+		// GLFW has some platform issues with keyboard handling that needs workaround until
+		// it's fixed properly in glfw. This code must not run on linux with glfw 3.0.4 (it
+		// has changed several times in the past). issue #10.
+#ifndef LINUX
 		// glfw calls key_callback instead of char_callback
 		// when pressing a character while ctrl is also pressed.
 		if (key_ctrl && !key_alt && key >= 32 && key <= 255)
 			InvokeKey(window, key, TB_KEY_UNDEFINED, modifier, down);
+#endif
 		break;
 	}
 }