* cygwin.din (_getutline): Remove.

* lib/bsdlib.cc (login): Make argument const as per linux.
(logout): Ditto.
* syscalls.cc (getutid): Ditto.
(getutline): Ditto.
(pututline): Ditto.
(getutxent): Add comment mentioning non-thread-safety.
(getutxid): Ditto.
(getutxline): Ditto.
(pututxline): Ditto.
* sys/utmp.h: Declare arguments to various functions as const as per linux.
Remove bogus _getutline definition.

winsup/cygwin/libc/bsdlib.cc

@@ -271,7 +271,7 @@ logwtmp (const char *line, const char *user, const char *host)
 }
 
 extern "C" void
-login (struct utmp *ut)
+login (const struct utmp *ut)
 {
   pututline (ut);
   endutent ();
@@ -279,7 +279,7 @@ login (struct utmp *ut)
 }
 
 extern "C" int
-logout (char *line)
+logout (const char *line)
 {
   struct utmp ut_buf, *ut;