Add "stylus" to the list of substrings in a device name that cause it to be recognized
as a GDK_SOURCE_PEN device (previously "wacom", "pen" and "eraser"). Some devices
just use "stylus" in their name, and are otherwise recognized as
GDK_SOURCE_TOUCHSCREEN instead.
Fixes #4394.
input_source = GDK_SOURCE_TABLET_PAD;
else if (strstr (tmp_name, "wacom") ||
strstr (tmp_name, "pen") ||
+ strstr (tmp_name, "stylus") ||
strstr (tmp_name, "eraser"))
input_source = GDK_SOURCE_PEN;
else if (!strstr (tmp_name, "mouse") &&