dthelp: Remove always on macro M_NOPAR which was just there to support ancient compilers that don't have 'void'

cde/programs/dthelp/parser/pass1/build/except.c

@@ -32,7 +32,7 @@ This product and information is proprietary of Tandem Computers Incorporated.
 #include "build.h"
 
 /* Add an exception (inclusion or exclusion) for the current element */
-void addex(M_NOPAR)
+void addex(void)
   {
     excount++ ;
     *nextex = (EXCEPTION *) m_malloc(sizeof(EXCEPTION), "exception") ;