bugreport: add uname info

The contents of uname() can give us some insight into what sort of
system the user is running on, and help us replicate their setup if need
be. The domainname field is not guaranteed to be available, so don't
collect it.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bugreport.c

@@ -7,10 +7,24 @@
 
 static void get_system_info(struct strbuf *sys_info)
 {
+	struct utsname uname_info;
+
 	/* get git version from native cmd */
 	strbuf_addstr(sys_info, _("git version:\n"));
 	get_version_info(sys_info, 1);
-	strbuf_complete_line(sys_info);
+
+	/* system call for other version info */
+	strbuf_addstr(sys_info, "uname: ");
+	if (uname(&uname_info))
+		strbuf_addf(sys_info, _("uname() failed with error '%s' (%d)\n"),
+			    strerror(errno),
+			    errno);
+	else
+		strbuf_addf(sys_info, "%s %s %s %s\n",
+			    uname_info.sysname,
+			    uname_info.release,
+			    uname_info.version,
+			    uname_info.machine);
 }
 
 static const char * const bugreport_usage[] = {