diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 346d1938898e..00bf1c09ceb3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2010-11-21  Joseph Myers  <joseph@codesourcery.com>
+
+	* system.h (strerror): Poison.
+
 2010-11-21  Richard Henderson  <rth@redhat.com>
 
 	* config/ia64/ia64.c (ia64_expand_builtin): Use the correct mode
diff --git a/gcc/system.h b/gcc/system.h
index 42332b3bd013..a6b01973e454 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -684,6 +684,12 @@ extern void fancy_abort (const char *, int, const char *) ATTRIBUTE_NORETURN;
  #pragma GCC poison malloc realloc
 #endif
 
+/* The %m format should be used when GCC's main diagnostic functions
+   supporting %m are available, and xstrerror from libiberty
+   otherwise.  */
+#undef strerror
+ #pragma GCC poison strerror
+
 /* Old target macros that have moved to the target hooks structure.  */
  #pragma GCC poison ASM_OPEN_PAREN ASM_CLOSE_PAREN			\
 	FUNCTION_PROLOGUE FUNCTION_EPILOGUE				\