Pulling in utmpx.h which does not have UT_HOSTSIZE, UT_LINESIZE & UT_NAMESIZE defined. Causing: w.c: In function 'print_from': w.c:236:43: error: 'UT_HOSTSIZE' undeclared (first use in this function) 236 | print_display_or_interface(u->ut_host, UT_HOSTSIZE, fromlen - len); | ^~~~~~~~~~~ w.c:236:43: note: each undeclared identifier is reported only once for each function it appears in w.c: In function 'getproc': w.c:357:12: error: 'UT_NAMESIZE' undeclared (first use in this function) 357 | char buf[UT_NAMESIZE + 1]; .... proc/escape.c:237:30: error: 'CODESET' undeclared (first use in this function) 237 | char *enc = nl_langinfo(CODESET); --- a/w.c +++ b/w.c @@ -55,11 +55,7 @@ #include #include #include -#ifdef HAVE_UTMPX_H -# include -#else -# include -#endif +#include #include static int ignoreuser = 0; /* for '-u' */ --- a/proc/escape.c +++ b/proc/escape.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "procps.h" #include "escape.h" #include "readproc.h"