(struct my_group): Added.

(getgrgid): Added.

src/mac.c

@@ -30,6 +30,7 @@ Boston, MA 02111-1307, USA.  */
 #include <sys/stat.h>
 #include <string.h>
 #include <pwd.h>
+#include <grp.h>
 #include <sys/param.h>
 #include <stdlib.h>
 #include <fcntl.h>
@@ -1164,6 +1165,13 @@ static struct passwd my_passwd =
   my_passwd_dir,
 };
 
+static struct group my_group =
+{
+  /* There are no groups on the mac, so we just return "root" as the
+     group name.  */
+  "root",
+};
+
 
 /* Initialized by main () in macterm.c to pathname of emacs directory.  */
 
@@ -1258,6 +1266,13 @@ getpwuid (uid_t uid)
 }
 
 
+struct group *
+getgrgid (gid_t gid)
+{
+  return &my_group;
+}
+
+
 struct passwd *
 getpwnam (const char *name)
 {