gcc's configure system has the nasty habit (for us) of judging for
itself if it is building a cross compiler (or cross compiling), but on
the limited information of the build, host and target platforms' config
which only contains a subset of the information we encode in
`stdenv.*Platform`. The practical consequence was that prior to this
change building `pkgsLLVM.buildPackages.gcc` actually fails because it
refuses to use `--with-headers` with something it believes to not be a
cross compiler.
As a workaround we force the appropriate variable in the configure
script to always be `yes` regardless of its own conditional check.
At some point we probably should report this issue in some capacity, so
future gcc versions don't force us into workarounds like this and
acdc783418.
The broken build of ghcHEAD on aarch64-linux results from rts/Libdw.c
not supporting that platform. Seemingly this particular file is only
relevant for DWARF support in GHC, so we disable that on unsupported
platforms.
This is in an effort to fix the following build failure shown by
chromium:
clang++: error: no such file or directory: '/nix/store/fhd89wrmkx6nflzjk0d6waz70bk3zc4i-clang-wrapper-12.0.0/resource-root/share/cfi_blacklist.txt'
As it turns out a change introduced via the gnu-install-dirs.patch
caused `add_compiler_rt_resource_file` to install resource files to
$dev/include (FULL_INCLUDEDIR) instead of $out/share (FULL_DATADIR)
which in turn meant that the clang wrappers we had didn't link those
files to its resource root at all.
Alternative fix to this would have been to link
compiler-rt.dev/include/*.txt to the wrappers resource-root/share as
well, but since this was handled inconsistently across the patch anyways
(the dfsan list is installed correctly), opt to handle this
consistently within the patch.
llvmPackages_{5,6} install the resource files to a completely different
location and need separate investigation.
7869d16545 changed how resource files are
installed. Likely by accident, now some of the resource files are
installed to $dev/include instead of $out/share. This causes the cc
wrapper's resource-root to miss those files from compiler-rt as they are
in a different place than expected.
This commit fixes all instances of this incorrect installation for
llvmPackages_10, 11 and 12 which are the only llvm package sets which
link ${targetLlvmLibraries.compiler-rt.out}/share to the resource-root.
For the other llvm package set this will likely also need to be fixed,
but it doesn't have to have immediate urgency and doing it in two steps
allows us to (hopefully) fix the chromium build without causing a darwin
stdenv rebuild.
The full fix can be found in #123103 and should probably be included in
the next staging-next rotation.
