clang-scan-deps can pick it up automatically from the first argument
now.
For the windows wrapper, keep passing -target, to allow running with
a potentially foreign clang-scan-deps.exe.
When setting up wrappers for Windows, rename clang-scan-deps.exe to
clang-scan-deps-real.exe, make clang-scan-deps.exe a wrapper, and
configure the wrapper to target executing clang-scan-deps-real.exe.
This makes sure that we always pass in crucial options like
-stdlib=libc++.
By default, our Clang executables are built with that option
hardcoded, configured with CLANG_DEFAULT_CXX_STDLIB=libc++
when built for Windows. However, we generally don't rely on this;
we assume the tools could be plain default executables, so we
try to provide wrappers on all common access paths.
This picks the architecture by looking for a triple prefix in the
nested command, and passes it as an explicit flag, to let
clang-scan-deps find it.
We also pass -stdlib=libc++, to let it find the libc++ headers
as expected.
Martin Storsjö