append-* has many variants:
- flags
- cppflags
- cflags
- cxxflags
Somehow we ended up using number 3, which doesn't include number 4,
despite which, wxGTK has mixed C / C++ sources that both use
GDK_WINDOWING_*.
Newer versions of my QA script do catch this -- tested locally. Since it
processes the RDEPEND file from metadata rather than ${RDEPEND}, it
knows that [wayland?] when it was *disabled* cannot still have the
relevant symbols... something only possible when the macro has been
typoed.
Closes: https://bugs.gentoo.org/961621
Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>