Honor CMAKE_INSTALL_BINDIR

[tristanlabelle]

CMake install places binary files under the CMAKE_INSTALL_BINDIR subdirectory, but some CMake files hardcode bin instead (the default value). This change un-hardcodes these. This has no effect by default, but it will allow redirecting the binaries to a different output directory, which will help with packaging installers for multiple architectures in the Windows build.

[compnerd]

https://github.com/apple/swift-corelibs-foundation/blob/main/CMakeLists.txt#L53 includes GNUInstallDirs so we should be fine.

[compnerd]

@swift-ci please test

[compnerd]

@swift-ci please test Linux platform

[tristanlabelle]

The Linux CI build is still hitting the seemingly unrelated:

/home/build-user/swift-tools-support-core/Sources/TSCBasic/ByteString.swift:11:8: error: no such module 'Foundation'
import Foundation
       ^

[compnerd]

@swift-ci please test Linux platform

[tristanlabelle]

The linux CI still failed on an apparently unrelated issue. It's succeeded building and failed in tests:

******************** TEST 'Swift-validation(linux-x86_64) :: stdlib/UnsafeBufferPointerSlices.swift' FAILED ********************
couldn't parse text: '://106656555'
in expression: 'rdar://106656555'
in REQUIRES: directive on test line 4
********************

[compnerd]

@swift-ci please test Linux platform

[tristanlabelle]

Ah! It looks like in the linux build, CMAKE_INSTALL_LIBDIR expands to lib/x86_64-linux-gnu

[tristanlabelle]

The latest change scopes down to only replacing bin with CMAKE_INSTALL_BINDIR and leaving lib alone given the variation of the linux build and that for the Windows installer purposes, we only need to override the bin dir. @compnerd , could you re-kick the CI?

[compnerd]

@swift-ci please test