diff --git a/winsup/cygwin/cygwin.din b/winsup/cygwin/cygwin.din
index 2e7e647..780179a 100644
--- a/winsup/cygwin/cygwin.din
+++ b/winsup/cygwin/cygwin.din
@@ -1933,6 +1933,7 @@ xdrrec_skiprecord SIGFE
 __xdrrec_getrec SIGFE
 __xdrrec_setnonblock SIGFE
 xdrstdio_create SIGFE
+__xpg_strerror_r SIGFE
 y0 NOSIGFE
 y0f NOSIGFE
 y1 NOSIGFE
diff --git a/winsup/cygwin/errno.cc b/winsup/cygwin/errno.cc
index a9860f4..91c381f 100644
--- a/winsup/cygwin/errno.cc
+++ b/winsup/cygwin/errno.cc
@@ -368,16 +368,23 @@ strerror (int errnum)
   return errstr;
 }

-#if 0
+/* Newlib provides the glibc strerror_r interface, but like Linux, we
+   also provide the POSIX interface.  POSIX leaves a lot of leeway,
+   but recommends that buf always be populated, and that both EINVAL
+   and ERANGE be returned when appropriate.  */
 extern "C" int
-strerror_r (int errnum, char *buf, size_t n)
+__xpg_strerror_r (int errnum, char *buf, size_t n)
 {
   char *errstr = strerror_worker (errnum);
+  int result = 0;
   if (!errstr)
-    return EINVAL;
+    {
+      __small_sprintf (errstr = _my_tls.locals.strerror_buf,
+		       "Unknown error %u", (unsigned) errnum);
+      result = EINVAL;
+    }
+  strncpy (buf, errstr, n);
   if (strlen (errstr) >= n)
-    return ERANGE;
-  strcpy (buf, errstr);
-  return 0;
+    result = ERANGE;
+  return result;
 }
-#endif
diff --git a/winsup/cygwin/include/cygwin/version.h b/winsup/cygwin/include/cygwin/version.h
index c757827..7246e8e 100644
--- a/winsup/cygwin/include/cygwin/version.h
+++ b/winsup/cygwin/include/cygwin/version.h
@@ -399,12 +399,13 @@ details. */
       233: Add TIOCGPGRP, TIOCSPGRP.  Export llround, llroundf.
       234: Export program_invocation_name, program_invocation_short_name.
       235: Export madvise.
+      236: Export __xpg_strerror_r.
      */

      /* Note that we forgot to bump the api for ualarm, strtoll, strtoull */

 #define CYGWIN_VERSION_API_MAJOR 0
-#define CYGWIN_VERSION_API_MINOR 235
+#define CYGWIN_VERSION_API_MINOR 236

      /* There is also a compatibity version number associated with the
 	shared memory regions.  It is incremented when incompatible