This fixes potential pointer truncation on 64 bit windows.
(Existing tests have ran fine in practice; either these are codepaths
not exercised in current setups, or potential codepaths that could
be triggered with more extensive tests.)
For compiler-rt and libunwind, this makes them build successfully even
if llvm-config and the llvm cmake files aren't available.
For libcxxabi, this brings in support for using SEH exceptions.
For libcxx, this removes a few build time warnings.
When building libcxx, this is also already enabled via the cmake
option -DLIBCXX_HAS_WIN32_THREAD_API=ON.
This fixes building libcxxabi if pthreads are available.
As long as we pass --sysroot explicitly in clang-target-wrapper.sh,
this isn't necessary. And since clang SVN r329946. it's no longer
necessary when not specifying the sysroot (and having it is in
fact harmful).
If the libcxx headers already have been installed, adding
-I$LIBCXX/include to the include path breaks some C standard
headers. The libcxx installation provides e.g. stdlib.h, which
does an #include_next <stdlib.h>. If the include path includes
both $LIBCXX/include and the libcxx headers installed to the
target sysroot, the #include_next will pick up the same header
from the next include directory. And due to include guards,
the second inclusion of the libcxx version of the header does
nothing at all, instead of doing yet another #include_next for
picking up the real version of the header.
By adding -nostdinc++, we avoid the possibly installed version
of these headers.
This fixes rebuilding libunwind after libcxx has been built
and installed.
Martin Storsjö