dtfile: Add missing prototypes

Add missing prototypes and header files to the dtfile
code in order to move closer towards 64-bit compatibility.

Extract the following functions from Motif internal headers:

_XmGetWidgetExtData
_XmRecordEvent
_XmStringUngenerate
_XmTextFieldSetDestination
_XmGetActiveTopLevelMenu

Extract manually prototypes of the obsolete Motif interface:
_XmHighlightBorder
_XmUnhighlightBorder

Remove XmPrivate.h if extractprototype.awk fails

Make the following header files available via -I:
	codelibs/boolean.h
	codelibs/pathutils.h
	codelibs/shellutils.h
and remove shellutils.h from dtwm directory.

cde/programs/dtfile/dtcopy/sharedFuncs.h

@@ -96,6 +96,6 @@ extern void      TimeoutHandler(
                                     XtPointer client_data,
                                     XtIntervalId *id);
 
-
+extern char *    get_path(char *path);
 
 #endif /* SHAREDFUNCS_H */