--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libiberty/xstrerror.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,79 @@
+/* xstrerror.c -- jacket routine for more robust strerror() usage.
+   Fri Jun 16 18:30:00 1995  Pat Rankin  <rankin@eql.caltech.edu>
+   This code is in the public domain.  */
+
+/*
+
+@deftypefn Replacement char* xstrerror (int @var{errnum})
+
+Behaves exactly like the standard @code{strerror} function, but
+will never return a @code{NULL} pointer.
+
+@end deftypefn
+
+*/
+
+#include <stdio.h>
+
+#include "config.h"
+#include "libiberty.h"
+
+#ifdef VMS
+#  include <errno.h>
+#  if !defined (__STRICT_ANSI__) && !defined (__HIDE_FORBIDDEN_NAMES)
+#    ifdef __cplusplus
+extern "C" {
+#    endif /* __cplusplus */
+extern char *strerror (int,...);
+#    define DONT_DECLARE_STRERROR
+#    ifdef __cplusplus
+}
+#    endif /* __cplusplus */
+#  endif
+#endif  /* VMS */
+
+
+#ifndef DONT_DECLARE_STRERROR
+#  ifdef __cplusplus
+extern "C" {
+#  endif /* __cplusplus */
+extern char *strerror (int);
+#  ifdef __cplusplus
+}
+#  endif /* __cplusplus */
+#endif
+
+/* If strerror returns NULL, we'll format the number into a static buffer.  */
+
+#define ERRSTR_FMT "undocumented error #%d"
+static char xstrerror_buf[sizeof ERRSTR_FMT + 20];
+
+/* Like strerror, but result is never a null pointer.  */
+
+char *
+xstrerror (int errnum)
+{
+  char *errstr;
+#ifdef VMS
+  char *(*vmslib_strerror) (int,...);
+
+  /* Override any possibly-conflicting declaration from system header.  */
+  vmslib_strerror = (char *(*) (int,...)) strerror;
+  /* Second argument matters iff first is EVMSERR, but it's simpler to
+     pass it unconditionally.  `vaxc$errno' is declared in <errno.h>
+     and maintained by the run-time library in parallel to `errno'.
+     We assume that `errnum' corresponds to the last value assigned to
+     errno by the run-time library, hence vaxc$errno will be relevant.  */
+  errstr = (*vmslib_strerror) (errnum, vaxc$errno);
+#else
+  errstr = strerror (errnum);
+#endif
+
+  /* If `errnum' is out of range, result might be NULL.  We'll fix that.  */
+  if (!errstr)
+    {
+      sprintf (xstrerror_buf, ERRSTR_FMT, errnum);
+      errstr = xstrerror_buf;
+    }
+  return errstr;
+}