Add replacement library files

lib/xstrdup.c

@@ -0,0 +1,22 @@
+/*
+ * xstrdup.c
+ *
+ * Simple error-checking version of strdup()
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+char *xstrdup(const char *s)
+{
+  char *p = strdup(s);
+
+  if ( !p ) {
+    fprintf(stderr, "Out of memory!\n");
+    exit(128);
+  }
+
+  return p;
+}