disable elfexec when statically linked

This currently is not supported by dj64dev.

Author: stsp

src/command.c

@@ -2684,7 +2684,7 @@ static void perform_echo(const char *arg)
 
 static void perform_elfexec(const char *arg)
   {
-#ifdef DJ64
+#if defined(DJ64) && !defined(STATIC_LINK)
   int rc;
 #endif
   if (!arg || !arg[0])
@@ -2693,7 +2693,7 @@ static void perform_elfexec(const char *arg)
     reset_batfile_call_stack();
     return;
     }
-#ifdef DJ64
+#if defined(DJ64) && !defined(STATIC_LINK)
   rc = elfexec(arg, 0, NULL);
   if (rc == -1)
     printf("elfexec failed\n");