diff --git a/newlib/ChangeLog b/newlib/ChangeLog
index b403baa59..5d7bd6c3d 100644
--- a/newlib/ChangeLog
+++ b/newlib/ChangeLog
@@ -1,3 +1,8 @@
+2002-01-28  Thomas Fitzsimmons  <fitzsim@redhat.com>
+
+	* libc/include/sys/signal.h [__CYGWIN__]: Issue error message
+	when _CYGWIN_TYPES_H is not defined.
+
 2002-01-24  Thomas Fitzsimmons  <fitzsim@redhat.com>
 
 	* libc/include/sys/signal.h: Revert 2002-01-23 change.
diff --git a/newlib/libc/include/sys/signal.h b/newlib/libc/include/sys/signal.h
index e3368bfb1..11d370ac4 100644
--- a/newlib/libc/include/sys/signal.h
+++ b/newlib/libc/include/sys/signal.h
@@ -159,6 +159,11 @@ int _EXFUN(sigsuspend, (const sigset_t *));
 int _EXFUN(sigpause, (int));
 
 #if defined(_POSIX_THREADS)
+#ifdef __CYGWIN__
+#  ifndef _CYGWIN_TYPES_H
+#    error You need the winsup sources or a cygwin installation to compile the cygwin version of newlib.
+#  endif
+#endif
 int _EXFUN(pthread_kill, (pthread_t thread, int sig));
 #endif