Build error "unable to load standard library for target" on PowerPC64/Ubuntu 16.04.

Hi,

As I have reported earlier, I am facing "unable to load standard library
for target" while building SwiftPM on ppc64le (PPC64 little endian
platform) for Ubuntu 16.04. The exact log of the error is as follows:

--- bootstrap: note: building self-hosted 'swift-build': env
SWIFT_EXEC=/root/swift-source/build/buildbot_incremental/swiftpm-linux-powerpc64le/ppc64le-unknown-linux/release/swiftc
SWIFT_BUILD_PATH=/root/swift-source/build/buildbot_incremental/swiftpm-linux-powerpc64le
/root/swift-source/build/buildbot_incremental/swiftpm-linux-powerpc64le/ppc64le-unknown-linux/release/swift-build-stage1
--disable-sandbox -Xlinker -rpath -Xlinker $ORIGIN/../lib/swift/linux
-Xlinker -L -Xlinker
/root/swift-source/build/buildbot_incremental/foundation-linux-powerpc64le/Foundation
-Xlinker -rpath -Xlinker
/root/swift-source/build/buildbot_incremental/foundation-linux-powerpc64le/Foundation
-Xswiftc
-I/root/swift-source/build/buildbot_incremental/foundation-linux-powerpc64le/Foundation
-Xswiftc
-I/root/swift-source/build/buildbot_incremental/foundation-linux-powerpc64le/Foundation/usr/lib/swift
-Xlinker -L -Xlinker
/root/swift-source/build/buildbot_incremental/xctest-linux-powerpc64le
-Xlinker -rpath -Xlinker
/root/swift-source/build/buildbot_incremental/xctest-linux-powerpc64le
-Xswiftc
-I/root/swift-source/build/buildbot_incremental/xctest-linux-powerpc64le
-Xlinker
-L/root/swift-source/build/buildbot_incremental/libdispatch-linux-powerpc64le/src/.libs
-Xswiftc
-I/root/swift-source/build/buildbot_incremental/libdispatch-linux-powerpc64le/src
-Xswiftc
-I/root/swift-source/build/buildbot_incremental/libdispatch-linux-powerpc64le/src/swift
-Xswiftc -I/root/swift-source/swift-corelibs-libdispatch -Xcc -fblocks
-Xswiftc -enable-testing --configuration release --build-tests
Compile clibc libc.c
Compile Swift Module 'PackageDescription4' (9 sources)
Compile Swift Module 'PackageDescription' (6 sources)
Compile Swift Module 'swiftpm_xctest_helper' (1 sources)
Compile Swift Module 'libc' (1 sources)
<unknown>:0: error: unable to load standard library for target
'ppc64le-unknown-linux'
<unknown>:0: error: unable to load standard library for target
'ppc64le-unknown-linux'
<unknown>:0: error: unable to load standard library for target
'ppc64le-unknown-linux'
error: terminated(1):
/root/swift-source/build/buildbot_incremental/swiftpm-linux-powerpc64le/ppc64le-unknown-linux/release/swift-build-tool
-f
/root/swift-source/build/buildbot_incremental/swiftpm-linux-powerpc64le/release.yaml
test
--- bootstrap: error: build failed with exit status 1
utils/build-script: fatal error: command terminated with a non-zero exit
status 1, aborting

This seems to have originated from CompilerInstance::loadStdlib() function,
which is calling Context->getStdlibModule(). At present I am trying to
understand this code. My primary inference is that the paths for libraries
being looked for is not correct. The libraries seem to be present under the
build directory, but they are not getting detected/picked up.

Is there any way I can specify the path to these libraries? I tried setting
LD_LIBRARY_PATH, but that did not help.

Thanks,
Atul.