Fix code formatting/style issues ...

... including, but not limited to:
- unused macros
- private functions not marked as static
- unprototyped global functions
- variable shadowing

(detected by various non-default GCC 8 warning options)
diff --git a/tjutil.c b/tjutil.c
index b44086d..e4f9b42 100644
--- a/tjutil.c
+++ b/tjutil.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C)2011 D. R. Commander.  All Rights Reserved.
+ * Copyright (C)2011, 2019 D. R. Commander.  All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -26,6 +26,8 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "tjutil.h"
+
 #ifdef _WIN32
 
 #include <windows.h>