Instead of having a symlink of the entire Facades directory for
Unified, we must now create a real directory and symlink each Facade
assembly, because there's one Facade assembly that can't be shared
between Unified and Classic (System.Drawing.Primitives.dll) because
it references monotouch.dll/Xamarin.iOS.dll.
If no sdk version (-sdk_version) is passed to the native
linker, it tries to infer the SDK version from the
path to the -syslibroot argument.
In our case we use a versioned path to Xcode, but a general
symlink without the SDK version:
/Applications/Xcode73.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk
which means ld picked up the Xcode version as the SDK version,
since that's the first number part of the path [1], so we'd
end up with libraries whose SDK version was 73.
So instead use an SDK path with the SDK version, so that ld
finds the SDK version instead of the Xcode version.
[1] 266f4401b9/src/ld/Options.cpp (L4005-L4020)https://bugzilla.xamarin.com/show_bug.cgi?id=41597
watchbcl uses mdb rebase from tools64, but adding a more "correct"
dependency when the mdb rebase occurs causes tools64 to be built
twice simultaneously (probably because we use submakes, so a different
make process also tries to build tools64).
So instead use a bigger hammer and just build tools64 completely
before building watchbcl.
Aleksey Kliger
Chris Hamons
Alexander Köplinger
Rolf Bjarne Kvinge
Sebastien Pouliot
Marek Safar
Zoltan Varga