Android triples include a version number, which makes direct triple
comparisons for per-target runtime directory searching not always work.
Instead, look for the triple with the highest compatible version number
and use that per-target runtime directory instead. This maintains the
existing fallback to a triple without any version number, but I'm hoping
we can remove that in the future. https://discourse.llvm.org/t/62717
discusses this further.
The one remaining triple mismatch after this is that Android armv7
triples usually have an environment of `androideabi`, which Clang
normalizes to `android`. If you use the `androideabi` triple when
building the runtimes with a per-target runtimes dir, the directory will
get created with `androideabi` in its name, but Clang's triple search
uses the normalized triple and will look for an `android` directory
instead. https://reviews.llvm.org/D140925 will fix that by normalizing
triples when creating the per-target runtimes directories as well.
Reviewed By: phosek, pirama
Differential Revision: https://reviews.llvm.org/D158476
Searching for target-specific standard library header and library paths
should perform fallback searches for targets, the same way searching for
the runtime libraries does. It's important for the header and library
searches to be consistent, otherwise we could end up using mismatched
headers and libraries. (See also https://reviews.llvm.org/D146664.)
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D159293
