diff --git a/cpukit/ChangeLog b/cpukit/ChangeLog
index 3424d8d053..3ab988c7ec 100644
--- a/cpukit/ChangeLog
+++ b/cpukit/ChangeLog
@@ -1,3 +1,7 @@
+2008-08-18	Ralf Corsepius <ralf.corsepius@rtems.org>
+
+	* aclocal/prog-cc.m4: Add -Wnested-externs.
+
 2008-08-18	Ralf Corsepius <ralf.corsepius@rtems.org>
 
 	* libnetworking/net/ppp_tty.c: Remove bogus local decl of
diff --git a/cpukit/aclocal/prog-cc.m4 b/cpukit/aclocal/prog-cc.m4
index c050b8a4fd..674b489b7f 100644
--- a/cpukit/aclocal/prog-cc.m4
+++ b/cpukit/aclocal/prog-cc.m4
@@ -28,7 +28,7 @@ test "$rtems_cv_gcc_pipe" = "yes" && CC="$CC --pipe"
 AS_IF([test "$GCC" = yes],[
 RTEMS_CFLAGS="$RTEMS_CFLAGS -Wall"
 # FIXME: This should be removed in production releases
-RTEMS_CFLAGS="$RTEMS_CFLAGS -Wimplicit-function-declaration -Wstrict-prototypes"
+RTEMS_CFLAGS="$RTEMS_CFLAGS -Wimplicit-function-declaration -Wstrict-prototypes -Wnested-externs"
 m4_if([$1],,[],[RTEMS_CFLAGS="$RTEMS_CFLAGS $1"])
 ])
 AC_SUBST(RTEMS_CFLAGS)