build: convert package manifest libraries to static

[compnerd]

Change PackageDescription to static which will enable SPM to avoid having to deal with Path alteration to execute the manifest on Windows. This also means that we no longer have to worry about the DT_RUNPATH/LC_RPATH on Linux and Darwin respectively.

Partially correct CompilerPluginSupport to build statically and no longer install. This is meant to be statically incorporated into PackageDescription which currently is not performed. This still raises the issue of public API surface as the static module is not visible externally (i.e. is not re-exported).

[neonichu]

@compnerd is this still relevant?

[compnerd]

Yeah, I think that we still want to do this - it avoids the need to alter the path and simplifies trying to debug certain things.

[compnerd]

@swift-ci please test

[compnerd]

@swift-ci please test

[jakepetroules]

@compnerd I think you need to rebase this before it's ready for review?

[dschaefer2]

Ankit made these dynamic to help with debugging.

Allow developing SwiftPM without the bootstrap script

This will allow building and using the swiftpm binary that was built
using swiftpm.

Not sure what scenarios he was referring to. But we should make sure we can still debug SwiftPM and it'll use these libraries from the dev environment as we change them.

[compnerd]

But we should make sure we can still debug SwiftPM and it'll use these libraries from the dev environment as we change them.

@dschaefer2 I suspect that this was due to the interpreted form of the manifest which has long since changed to the executable form and that avoids any multiply defined symbols.