diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 091cbb1df3cf..596dd57fe0c0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Olivier Hainque  <hainque@adacore.com>
+
+	PR target/81755
+	* config/vxworksae.h (VXWORKS_HAVE_TLS): Define.
+
 2017-08-07  Douglas Rupp  <rupp@adacore.com>
 
 	* Makefile.in (install-mkheaders): Fix typo, where the multi_dir
diff --git a/gcc/config/vxworksae.h b/gcc/config/vxworksae.h
index 7e65907252a1..3b0b6529b8a7 100644
--- a/gcc/config/vxworksae.h
+++ b/gcc/config/vxworksae.h
@@ -68,6 +68,10 @@ along with GCC; see the file COPYING3.  If not see
   while (0)
 
 /* Do VxWorks-specific parts of TARGET_OPTION_OVERRIDE.  */
+
+/* None of the VxWorks AE/653/MILS ports to date has native TLS support.  */
+#define VXWORKS_HAVE_TLS 0
+
 #undef VXWORKS_OVERRIDE_OPTIONS
 #define VXWORKS_OVERRIDE_OPTIONS vxworks_override_options ()
 extern void vxworks_override_options (void);