Inside the Flatpak the bundled toolchain compiled every bootstrap object,
then glslang's configure failed its test link with `unable to find
library -lc++`. clang searches its per-target runtime directory
(lib/<triple>) and the system library paths for libc++, not
<prefix>/lib, so with the classic layout a toolchain outside /usr needs
the search path spelled out, just as its loader needs the rpath.
LibcxxLinkFlags and build.sh now emit both, the same pair an explicit
CRAFTER_BUILD_LIBCXX_DIR already got.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Jorijn van der Graaf
d22a8603df