In both cases, the maintainers state that the right
solution is to not do -I
/usr/include. AFAICT, this means there are two options:
Not really no ...
They say to not use the -isystem /usr/include
My opinion there is that qmake is broken doing the translation from
-Ixxx to -isystem xxx blindly when both don't have _exactly_ the same
semantic. QMake should check the system include list when doing the
translation and omit the system ones to compensate for the difference
of behavior of -I vs -isystem.
(a) Don't export -I /usr/include in the .pc file.
(b) Manually remove -I /usr/include for anyone who compiles with GCC 6 and
needs to use rtl-sdr.
Solution (a) seems cleaner to me. If you have another way that avoids
breaking packages that include rtl-sdr and use GCC 6, I'm happy to hear it.
Well (a) is fine ... but you can only remove /usr/include ... not ${includedir}
So you need to test is includedir is indeed /usr/include and then you
can omit it but if not, then you need to leave it.
Cheers,
Sylvain