Support the GNU-specific syntax ".IP \\[bu]" for bullet lists in man(7)

pages that Alejandro Colomar recommends in the "Lists" subsection of
https://man7.org/linux/man-pages/man7/man-pages.7.html#STYLE_GUIDE .

For example, this will improve HTML formatting of the first list in
the subsection "Feature test macros understood by glibc" on the page
https://manpages.debian.org/bookworm/manpages/ftm.7.en.html .

Issue reported by Alejandro Colomar <alx at kernel dot org>.

diff --git a/usr.bin/mandoc/man_html.c b/usr.bin/mandoc/man_html.c
index 5e0bffe..581f837 100644 (file)
--- a/usr.bin/mandoc/man_html.c
+++ b/usr.bin/mandoc/man_html.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: man_html.c,v 1.138 2023/04/28 20:14:19 schwarze Exp $ */
+/* $OpenBSD: man_html.c,v 1.139 2023/10/18 16:11:29 schwarze Exp $ */
 /*
  * Copyright (c) 2013-2015,2017-2020,2022 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2008-2012, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -431,10 +431,12 @@ list_continues(const struct roff_node *n1, const struct roff_node *n2)
        s2 = n2 == NULL ? "" : n2->string;
        c1 = strcmp(s1, "*") == 0 ? '*' :
             strcmp(s1, "\\-") == 0 ? '-' :
-            strcmp(s1, "\\(bu") == 0 ? 'b' : ' ';
+            strcmp(s1, "\\(bu") == 0 ? 'b' :
+            strcmp(s1, "\\[bu]") == 0 ? 'b' : ' ';
        c2 = strcmp(s2, "*") == 0 ? '*' :
             strcmp(s2, "\\-") == 0 ? '-' :
-            strcmp(s2, "\\(bu") == 0 ? 'b' : ' ';
+            strcmp(s2, "\\(bu") == 0 ? 'b' :
+            strcmp(s2, "\\[bu]") == 0 ? 'b' : ' ';
        return c1 != c2 ? '\0' : c1 == 'b' ? '*' : c1;
 }