[Bug c++/105851] Error: "Duplicate key positions selected" when recreating cfns.h

[qcorba at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105851

--- Comment #4 from Eric Tang <qcorba at gmail dot com> ---
(In reply to Andreas Schwab from comment #3)
> $$ is makefile quoting, you need to resolve the quoting manually if you want
> to run the command outside of make.

Is there a means to check that?

I removed cfns.h and configured with --enable-maintainer-mode but the header
file was not recreated and build failed with:
../.././gcc/cp/except.c:1023:18: fatal error: cfns.h: No such file or directory
compilation terminated.