This one is a bit less immediate than the vmctl one: /usr/src/usr.bin/yacc/output.c:908:26: warning: comparing a pointer to a null character constant; did you mean to compare to NULL? [-Wpointer-compare] if ((s = symnam[i]) != '\0') { ^~~~ (void *)0
This time the suggestion is correct. It used to be 'if (s = symnam[i])' and the incorrect spelling of NULL was chosen in a -Wall cleanup 19 years ago (-r 1.6). Upstream uses a naked 0 instead of NULL, so does NetBSD. Index: output.c =================================================================== RCS file: /var/cvs/src/usr.bin/yacc/output.c,v retrieving revision 1.27 diff -u -p -r1.27 output.c --- output.c 23 May 2020 21:08:38 -0000 1.27 +++ output.c 2 Sep 2020 20:44:13 -0000 @@ -905,7 +905,7 @@ output_debug(void) "\t{", symbol_prefix); j = 80; for (i = 0; i <= max; ++i) { - if ((s = symnam[i]) != '\0') { + if ((s = symnam[i]) != NULL) { if (s[0] == '"') { k = 7; while (*++s != '"') {