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.

…r-log.a.

This was already done for iOS device builds [1], this does the same thing for
all the other builds (simulator, tvOS, watchOS).

[1] xamarin/maccore@f773a69

Mono disabled building the log profiler as a dynamic library [1],
so don't try to install it.

[1] mono/mono@cfd9870