Issue Description:

If the LD_LIBRARY_PATH environment variable has contents in the local shell, running:

{{./swift/utils/build-script --preset=buildbot_linux install_destdir="/tmp/install" installable_package="/tmp/swift.tar.gz"
}}

Results in:

{{
Exit Code: 1

Command Output (stderr):

/home/x/devel/git_projects/swift_repos/swift_build/swift/test/Driver/options-interpreter.swift:21:35: error: expected string not found in input
// CHECK-RESOURCE-DIR-ONLY-LINUX: # LD_LIBRARY_PATH=/RSRC/linux{{$}}
^
<stdin>:1:1: note: scanning from here
/home/x/devel/git_projects/swift_repos/swift_build/build/buildbot_linux/swift-linux-x86_64/bin/swift -frontend -interpret /home/x/devel/git_projects/swift_repos/swift_build/swift/test/Driver/options-interpreter.swift -target x86_64-unknown-linux-gnu -disable-objc-interop -module-cache-path /tmp/swift-testsuite-clang-module-caches0WIiy -resource-dir /RSRC/ -module-name main # LD_LIBRARY_PATH=/RSRC/linux:/home/x/.gvm/pkgsets/go1.5/global/overlay/lib:/home/x/.gvm/pkgsets/go1.5/global/overlay/lib:/home/x/.gvm/pkgsets/go1.5/global/overlay/lib::/home/x/cuda-5.5/lib64:/home/x/cuda-5.5/lib
^
<stdin>:1:389: note: possible intended match here
/home/x/devel/git_projects/swift_repos/swift_build/build/buildbot_linux/swift-linux-x86_64/bin/swift -frontend -interpret /home/x/devel/git_projects/swift_repos/swift_build/swift/test/Driver/options-interpreter.swift -target x86_64-unknown-linux-gnu -disable-objc-interop -module-cache-path /tmp/swift-testsuite-clang-module-caches0WIiy -resource-dir /RSRC/ -module-name main # LD_LIBRARY_PATH=/RSRC/linux:/home/x/.gvm/pkgsets/go1.5/global/overlay/lib:/home/x/.gvm/pkgsets/go1.5/global/overlay/lib:/home/x/.gvm/pkgsets/go1.5/global/overlay/lib::/home/x/cuda-5.5/lib64:/home/x/cuda-5.5/lib
^

--

********************
Testing Time: 456.07s
********************
Failing Tests (2):
Swift :: Driver/environment.swift
Swift :: Driver/options-interpreter.swift

Expected Passes : 7228
Expected Failures : 83
Unsupported Tests : 654
Unexpected Failures: 2

• • • Failed while running tests for swift (check-swift-all-linux-x86_64)
      swift/utils/build-script: command terminated with a non-zero exit status 1, aborting
      swift/utils/build-script: command terminated with a non-zero exit status 1, aborting
      }}

After performing:

unset LD_LIBRARY_PATH

Re-running the build command succeeds.