by the final warning state after processing all the toplevel
input files (including Final.sd.mk).
-&:local+global [&]VARIABLE ...
+&:local+global [!][&]VARIABLE ...
Suppresses any warnings relating to forthcoming mentions
to VARIABLE or &VARIABLE, as applicable. Scope ends at
the end of the current directory's Suffix.sd.mk.
+ Prefixing with ! removes [&]VARIABLE from the suppresion list.
&:changequote NEWQUOTE
changes the escape sequence from & to literally NEWQUOTE