QMake ignored every extra compiler that sets variable_out and whose
output does not have a builtin compiler (C++, C).
What the code wants to achieve is to ignore extra compilers that put
their output into variables that are handled "somewhere else already",
e.g. are in the otherFilters list. Evidence for that is to be found in
the addOnInput == true if branch.
Task-number: QTBUG-71283
Change-Id: I8c1d76febccacb450cd14ad7a1f4b87726832312
Reviewed-by: Brett Stottlemyer <bstottle@ford.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
2dcfaf7bee