detect strerror_r and if not there, provide it

cf/roken-frag.m4

@@ -354,6 +354,7 @@ AC_BROKEN([					\
 	strcasecmp				\
 	strdup					\
 	strerror				\
+	strerror_r				\
 	strftime				\
 	strlcat					\
 	strlcpy					\

lib/roken/roken.h.in

@@ -306,6 +306,12 @@ int ROKEN_LIB_FUNCTION getdtablesize(void);
 char * ROKEN_LIB_FUNCTION strerror(int);
 #endif
 
+#if !defined(HAVE_STRERROR) && !defined(strerror)
+#define strerror_r rk_strerror_r
+int ROKEN_LIB_FUNCTION strerror_r(int, char *, size_t);
+#endif
+
+
 #if !defined(HAVE_HSTRERROR) || defined(NEED_HSTRERROR_PROTO)
 #ifndef HAVE_HSTRERROR
 #define hstrerror rk_hstrerror

lib/roken/strerror_r.c

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 1995, 1996, 1997, 1998 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden).
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+extern int sys_nerr;
+extern char *sys_errlist[];
+
+char* ROKEN_LIB_FUNCTION
+strerror_r(int eno, char *strerrbuf, size_t buflen)
+{
+    int ret;
+    if(eno < 0 || eno >= sys_nerr) {
+	snprintf(strerrbuf, buflen, "Error %d occurred.", eno);
+	return EINVAL;
+    }
+    ret = snprintf(strerrbuf, buflen, "%s", sys_errlist[eno]);
+    if (ret > buflen)
+	return ERANGE;
+    return 0;
+}