Swift 5.1 toolchain failure on ppc64le ubuntu 16.04

The following command to build swift 5.1 toolchain is failing on ubuntu 16.04 on powerpc64le:-
./swift/utils/build-toolchain swift_toolchain_ppc64le

Following is the failure part:-

./utils/build-script: note: Using toolchain default
+ mkdir -p /home/sar/swift-source/build/buildbot_linux
+ rm -rf /home/sar/swift-source/build/buildbot_linux/ninja-build
+ cp -r /home/sar/swift-source/ninja /home/sar/swift-source/build/buildbot_linux/ninja-build
+ pushd /home/sar/swift-source/build/buildbot_linux/ninja-build
+ env CXX=/usr/bin/clang++ /usr/bin/python configure.py --bootstrap
bootstrapping ninja...
./src/browse.cc:21:10: fatal error: 'vector' file not found
#include <vector>
         ^
1 error generated.
when running:  /usr/bin/clang++ -MMD -MT build/browse.o -MF build/browse.o.d -g -Wall -Wextra -Wno-deprecated -Wno-missing-field-initializers -Wno-unused-parameter -fno-rtti -fno-exceptions -fvisibility=hidden -pipe '-DNINJA_PYTHON="python"' -O2 -DNDEBUG -fdiagnostics-color -DUSE_PPOLL -DNINJA_HAVE_BROWSE -I. -c ./src/browse.cc -o build/browse.o
Traceback (most recent call last):
  File "configure.py", line 465, in <module>
    objs += cxx('browse', order_only=built('browse_py.h'))
  File "configure.py", line 282, in cxx
    return n.build(built(name + objext), 'cxx', src(name + '.cc'), **kwargs)
  File "configure.py", line 164, in build
    self._run_command(self._expand(cmd, local_vars))
  File "configure.py", line 189, in _run_command
    subprocess.check_call(cmdline, shell=True)
  File "/usr/lib/python2.7/subprocess.py", line 541, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '/usr/bin/clang++ -MMD -MT build/browse.o -MF build/browse.o.d -g -Wall -Wextra -Wno-deprecated -Wno-missing-field-initializers -Wno-unused-parameter -fno-rtti -fno-exceptions -fvisibility=hidden -pipe '-DNINJA_PYTHON="python"' -O2 -DNDEBUG -fdiagnostics-color -DUSE_PPOLL -DNINJA_HAVE_BROWSE -I. -c ./src/browse.cc -o build/browse.o' returned non-zero exit status 1
./utils/build-script: fatal error: command terminated with a non-zero exit status 1, aborting
./utils/build-script: fatal error: command terminated with a non-zero exit status 1, aborting

I have made sure all the dependencies installed as per the buildscript at "https://github.com/ppc64le/build-scripts/blob/master/swift/swift51_ubuntu_16.04.sh"
However, still facing above issues.

Seems to be trying to bootstrap Ninja, but the script seems to install it already in the machine (you can check if ninja actually works). If you want to skip that, maybe comment the build-ninja line in the [preset: mixin_linux_installation] section of utils/build-presets.ini, and see if that gets you further.