diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 0b4871c2d26..a38990f3b45 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,7 @@
+2019-07-11  Arnaud Charlet  <charlet@adacore.com>
+
+	* errno.c: Remove obsolete support for MaRTE OS.
+
 2019-07-11  Ed Schonberg  <schonberg@adacore.com>
 
 	* exp_ch4.adb (Expand_N_Type_Conversion): If a predicate check
diff --git a/gcc/ada/errno.c b/gcc/ada/errno.c
index a64ae876d5b..18f14ea06b3 100644
--- a/gcc/ada/errno.c
+++ b/gcc/ada/errno.c
@@ -35,21 +35,10 @@
    as it may be defined using a macro.
 */
 
-
+#ifndef _REENTRANT
 #define _REENTRANT
-#define _THREAD_SAFE
-
-#ifdef MaRTE
-
-/* MaRTE OS provides its own implementation of errno related functionality. We
-   want to ensure the use of the MaRTE version for tasking programs (the MaRTE
-   library will not be linked if no tasking constructs are used), so we use the
-   weak symbols mechanism to use the MaRTE version whenever is available. */
-
-#pragma weak __get_errno
-#pragma weak __set_errno
-
 #endif
+#define _THREAD_SAFE
 
 #include <errno.h>
 int