Unbreak on FreeBSD
../clients/window.c:42:10: fatal error: 'sys/epoll.h' file not found
#include <sys/epoll.h>
^~~~~~~~~~~~~
../shared/xalloc.c:39:28: error: use of undeclared identifier 'program_invocation_short_name'
fprintf(stderr, "[%s] ", program_invocation_short_name);
^