<!-- this runs the source-build bootstrap path as described in https://github.com/dotnet/fsharp/blob/95df49e380ea8dbf33653fa4209f89dba29413f5/eng/build.sh#L247
Note that we *are not* passing -source-build here so we do this bootstrap build in the outer build.
the important parts here are:
-bootstrap will build the "Proto" config of F# which includes tools and a bootstrap compiler
-skipBuild skips the rest of the build
-bl enables the binlogs for the tools and Proto builds, which make debugging failures here easier