is duplicated by:

• SR-6851 Implementing Collection and SetAlgebra on generic class type parameter makes isEmpty ambiguous

relates to:

• SR-10625 tests for -static-*

Issue Description:

Prelude (on OSX)

*Note*: swift 4.0.2 is used as an example, the `build_ubuntu_cross_compilation_toolchain` script is from `e36eebf5` (mid-november 2017)

1. `curl -o swift-4.0.2-RELEASE-ubuntu16.04.tar.gz https://swift.org/builds/swift-4.0.2-release/ubuntu1604/swift-4.0.2-RELEASE/swift-4.0.2-RELEASE-ubuntu16.04.tar.gz`

2. `curl -o swift-4.0.2-RELEASE-osx.pkg https://swift.org/builds/swift-4.0.2-release/xcode/swift-4.0.2-RELEASE/swift-4.0.2-RELEASE-osx.pkg`

3. `<path_to_swiftpm>/Utilities/build_ubuntu_cross_compilation_toolchain /tmp/ swift-4.0.2-RELEASE-osx.pkg swift-4.0.2-RELEASE-ubuntu16.04.tar.gz`

4. `mkdir Test`

5. `cd Test`

6. `swift package init --type=executable`

First broken case: --static-swift-stdlib

7. `swift build --static-swift-stdlib --destination=/tmp/cross-toolchain/ubuntu-xenial-destination.json`

8. Upload resulting binary to Ubuntu, I prefer to use docker to test with the `ubuntu:16.04` image: `docker run -ti -v (pwd):/test ubuntu:16.04 /test/.build/linux-unknown-x86_64/debug/Test`

*Observed*: `/test/.build/linux-unknown-x86_64/debug/Test: error while loading shared libraries: libswiftCore.so: cannot open shared object file: No such file or directory`

*Expected*: Binary prints "Hello, World!"

Note: Running on docker image `swift:4.0.2` with LD_LIBRARY_PATH pointing to libswiftCore.so works as expected

Second broken case: partial workaround with -Xswiftc -static-stdlib

7. `swift build -Xswiftc -static-stdlib --destination=/Users/george/Developer/Apple/cross-toolchain/ubuntu-xenial-destination.json`

*Observed*: `

clang: error: no such file or directory: '/usr/lib/x86_64-linux-gnu/libicui18n.a'

clang: error: no such file or directory: '/usr/lib/x86_64-linux-gnu/libicuuc.a'

clang: error: no such file or directory: '/usr/lib/x86_64-linux-gnu/libicudata.a'

`

Note that clang is looking for the libraries in `/usr/lib`, but the files are located in `/tmp/cross-toolchain/ubuntu-xenial.sdk/usr/lib/`

*Expected*: The executable is compiled successfully