Add set_program_name and get_program_name functions to cache argv[0].

main.cc

@@ -127,6 +127,17 @@ static BOOL OpenLibs(void) {
 /* global options */
 extern NmapOps o;  /* option structure */
 
+/* A mechanism to save argv[0] for code that requires that. */
+static const char *program_name = NULL;
+
+static void set_program_name(const char *name) {
+  program_name = name;
+}
+
+const char *get_program_name(void) {
+  return program_name;
+}
+
 int main(int argc, char *argv[]) {
   /* The "real" main is nmap_main().  This function hijacks control at the
      beginning to do the following:
@@ -141,6 +152,8 @@ int main(int argc, char *argv[]) {
   int ret;
   int i;
 
+  set_program_name(argv[0]);
+
 #ifdef __amigaos__
 	if(!OpenLibs()) {
 		error("Couldn't open TCP/IP Stack Library(s)!");

nmap.cc

@@ -138,6 +138,8 @@ extern char *optarg;
 extern int optind;
 extern NmapOps o;  /* option structure */
 
+/* argv[0] storage from main.cc. */
+extern const char *get_program_name(void);
 static bool target_needs_new_hostgroup(std::vector<Target *> &targets,
   const Target *target);
 static void display_nmap_version();