First victim was x11/qt6/qtbase ld: error: undefined symbol: backtrace
It's just a typo:
> diff --git a/x11/qt6/qtbase/Makefile b/x11/qt6/qtbase/Makefile
> index decd207f5d0..15fc859c01f 100644
> --- a/x11/qt6/qtbase/Makefile
> +++ b/x11/qt6/qtbase/Makefile
> @@ -105,7 +105,7 @@ CONFIGURE_ARGS += -DCMAKE_INSTALL_PREFIX=${PREFIX} \
> -DQT_FEATURE_openssl_linked=ON \
> -DQT_FEATURE_dtls=OFF
>
> -LDFLAGS += -lexecinfo
> +MOCMAKE_LDFLAGS += -lexecinfo
^
missing D in MODCMAKE_LDFLAGS
