dtcreate: Add missing prototypes and more (64-bit)

- Fix missing prototypes
- Fix some 64-bit related problems (XtVaGetValues)
- Fix crash on dtcreate startup in create_applicationShell1()
- Add XmeFlushIconFileCache() prototype from <Xm/IconFileP.h>

cde/programs/dtcreate/Confirmed.c

@@ -35,6 +35,7 @@
 #include <sys/signal.h>
 
 #include "dtcreate.h"
+#include "ca_aux.h"
 #include "UxXt.h"
 #include "CreateActionAppShell.h"