[PATCH 3/3] maint: port to GCC 8

[Paul Eggert]

* src/chown-core.h (chopt_free, gid_to_name, uid_to_name):
No longer const.
* src/make-prime-list.c (xalloc): Add malloc attribute.
* src/who.c (make_id_equals_comment): Work around GCC bug 85602
by using mempcpy rather than strncat.  Although the old code
was correct, strncat raises so many hackles that it’s not
worth maintaining its use here.
---
 src/chown-core.h      |  9 +++------
 src/make-prime-list.c |  2 +-
 src/who.c             | 12 ++++++++----
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/chown-core.h b/src/chown-core.h
index 26d702e2c..346b1cea4 100644
--- a/src/chown-core.h
+++ b/src/chown-core.h
@@ -68,14 +68,11 @@ struct Chown_option
 void
 chopt_init (struct Chown_option *);
 
-void _GL_ATTRIBUTE_PURE _GL_ATTRIBUTE_CONST
-chopt_free (struct Chown_option *);
+void chopt_free (struct Chown_option *);
 
-char *
-gid_to_name (gid_t);
+char *gid_to_name (gid_t) _GL_ATTRIBUTE_MALLOC;
 
-char * _GL_ATTRIBUTE_PURE
-uid_to_name (uid_t);
+char *uid_to_name (uid_t) _GL_ATTRIBUTE_MALLOC;
 
 bool
 chown_files (char **files, int bit_flags,
diff --git a/src/make-prime-list.c b/src/make-prime-list.c
index b41f9837c..1fb1677bf 100644
--- a/src/make-prime-list.c
+++ b/src/make-prime-list.c
@@ -157,7 +157,7 @@ output_primes (const struct prime *primes, unsigned nprimes)
   printf ("#define FIRST_OMITTED_PRIME %u\n", p);
 }
 
-static void *
+static void * _GL_ATTRIBUTE_MALLOC
 xalloc (size_t s)
 {
   void *p = malloc (s);
diff --git a/src/who.c b/src/who.c
index 6d9e267d9..3719baec5 100644
--- a/src/who.c
+++ b/src/who.c
@@ -447,10 +447,14 @@ print_boottime (const STRUCT_UTMP *utmp_ent)
 static char *
 make_id_equals_comment (STRUCT_UTMP const *utmp_ent)
 {
-  char *comment = xmalloc (strlen (_("id=")) + sizeof UT_ID (utmp_ent) + 1);
-
-  strcpy (comment, _("id="));
-  strncat (comment, UT_ID (utmp_ent), sizeof UT_ID (utmp_ent));
+  char const *ideq = _("id=");
+  char const *ut_id = UT_ID (utmp_ent);
+  size_t ideqlen = strlen (ideq);
+  size_t ut_idlen = strnlen (ut_id, sizeof UT_ID (utmp_ent));
+  char *comment = xmalloc (ideqlen + ut_idlen + 1);
+  char *rhs = mempcpy (comment, ideq, ideqlen);
+  char *z = mempcpy (rhs, ut_id, ut_idlen);
+  *z = '\0';
   return comment;
 }
 
-- 
2.17.0