Passing NULL to wlr_keyboard_set_keymap results in a segfault.
Example:
Thread 1 "dwl" received signal SIGSEGV, Segmentation fault.
0x00007ffff7e49b64 in xkb_keymap_ref () from /usr/lib/libxkbcommon.so.0
(gdb) bt
#0 0x00007ffff7e49b64 in xkb_keymap_ref () at /usr/lib/libxkbcommon.so.0
#1 0x00007ffff7f06389 in wlr_keyboard_set_keymap () at /usr/lib/libwlroots.so.11
#2 0x000055555555bc54 in createkeyboard ()
#3 0x000055555555c283 in inputdevice ()
#4 0x00007ffff7e8101e in wl_signal_emit_mutable () at /usr/lib/libwayland-server.so.0
#5 0x00007ffff7e8101e in wl_signal_emit_mutable () at /usr/lib/libwayland-server.so.0
#6 0x00007ffff7edb52c in () at /usr/lib/libwlroots.so.11
#7 0x00007ffff7ee44b6 in () at /usr/lib/libwlroots.so.11
#8 0x000055555555fe66 in main ()
