When reading a program name from the syslog configuration file,

do not stop copying it into a buffer when encountering a
non-alphanumerical character.  Only stop at unprintable characters.
This makes syslogd work correctly with executables like `interp.bin',
`httpd_old', etc.

PR:		misc/40941
MFC after:	1 week

usr.sbin/syslogd/syslogd.c

@@ -1449,7 +1449,7 @@ init(int signo)
 				continue;
 			}
 			for (i = 0; i < NAME_MAX; i++) {
-				if (!isalnum(p[i]))
+				if (!isprint(p[i]))
 					break;
 				prog[i] = p[i];
 			}