rastermann

patch inline: watch_displays_using_udev when it finds zero connected screens crashes

12

Asan found this baby: ``` ================================================================= ==62810==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000007091 at pc 0x7f167dd1795e bp 0x7f1678331cc0 sp 0x7f1678331468 READ of size 2 at 0x602000007091 thread T3 (watch_displays) #0 0x7f167dd1795d...