add a compatible memrchr() function if the platform does not support it (e.g. old glibc). Patch courtesy to Thomas Jarosch

src/libstrongswan/utils/lexparser.c

@@ -20,6 +20,9 @@
 
 #include "lexparser.h"
 
+#ifndef HAVE_MEMRCHR
+void *memrchr(const void *s, int c, size_t n);
+#endif
 
 /**
  * eat whitespace

src/libstrongswan/utils/memrchr.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2008 Thomas Jarosch
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#ifndef HAVE_MEMRCHR
+
+#include <string.h>
+
+void *memrchr(const void *s, int c, size_t n)
+{
+	unsigned char *reverse_search;
+
+	if (s == NULL || n == 0)
+	{
+		return NULL;
+	}
+
+	reverse_search = s + n;
+
+	for (;;)
+	{
+		if (*reverse_search == (unsigned char)c)
+		{
+			return reverse_search;
+		}
+		else if (reverse_search == s)
+		{
+			break;
+		}
+		reverse_search--;
+	}
+	return NULL;
+}
+
+#endif