MARK>
* MARK> ( -- DP-mark ) compile-only

makes room for a pointer in the dictionary to
be resolved through RESOLVE> and does therefore
memorize that cell's address on the CS-STACK
Mostly used after BRANCH or ?BRANCH in compiling
words like IF or ELSE
 simulate:
   : MARK> ?COMP  HERE 0 , ;

FORTH/BASE system ordinary primitive