Reduce use of utils.h for error functions

utils.cc

@@ -131,6 +131,7 @@
 
 #include "nmap.h"
 #include "utils.h"
+#include "nmap_error.h"
 #include "NmapOps.h"
 
 #include <fcntl.h>
@@ -191,14 +192,6 @@ void nmap_hexdump(unsigned char *cp, unsigned int length) {
 }
 
 
-#ifndef HAVE_STRERROR
-char *strerror(int errnum) {
-  static char buf[1024];
-  sprintf(buf, "your system is too old for strerror of errno %d\n", errnum);
-  return buf;
-}
-#endif
-
 /* Like the perl equivalent, removes the terminating newline from string IF one
    exists. It then returns the POSSIBLY MODIFIED string. */
 char *chomp(char *string) {