bin/59223: Build failure on Solaris-11.4 for src/include/regex.h

[cryintothebluesky%gmail.com@localhost]

>Number:         59223
>Category:       bin
>Synopsis:       Build failure on Solaris-11.4 for src/include/regex.h
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar 26 17:25:00 +0000 2025
>Originator:     Sad Clouds
>Release:        NetBSD-10
>Organization:
>Environment:
SunOS t4-node1 5.11 11.4.42.111.0 sun4v sparc sun4v non-virtualized

>Description:
Building NetBSD-10 with build.sh fails:

In file included from /opt/netbsd/netbsd-10-src/tools/compat/regex.h:3,
                 from /opt/netbsd/netbsd-10-src/tools/mandoc/../../external/bsd/mdocml/bin/mandoc/../../dist/dba_read.c:22:
/opt/netbsd/netbsd-10-src/tools/compat/../../include/regex.h:135:14: error: expected ';' before 'int'
  135 | __BEGIN_DECLS
      |              ^
      |              ;
  136 | int     regcomp(regex_t * __restrict, const char * __restrict, int);
      | ~~~           
/opt/netbsd/netbsd-10-src/tools/compat/../../include/regex.h:145:12: error: expected ';' before 'extern'
  145 | __END_DECLS
      |            ^
      |            ;


I think these macros are not portable and probably obsolete.
>How-To-Repeat:

>Fix:
$ diff -u src/include/regex.h.orig src/include/regex.h
--- src/include/regex.h.orig    2025-03-26 09:19:45.655609768 +0000
+++ src/include/regex.h 2025-03-26 09:15:38.998649758 +0000
@@ -132,7 +132,10 @@
 #define        REG_LARGE       01000   /* force large representation */
 #define        REG_BACKR       02000   /* force use of backref code */
 
-__BEGIN_DECLS
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 int    regcomp(regex_t * __restrict, const char * __restrict, int);
 size_t regerror(int, const regex_t * __restrict, char * __restrict, size_t);
 int    regexec(const regex_t * __restrict,
@@ -142,6 +145,9 @@
 ssize_t regnsub(char *, size_t, const char *, const regmatch_t *, const char *);
 ssize_t regasub(char **buf, const char *, const regmatch_t *, const char *);
 #endif
-__END_DECLS
 
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
 #endif /* !_REGEX_H_ */