<FORTH-83>
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 , ;
reference: p4_forward_mark in ../src/forth-83.c:0198, export CO MARK>