Thanks for the detailed report.

Could you try to use the latest python2 instead of 2.7.13 to see if this solves it?

Change 2.7.13 for 2.7.15 in these 2 lines in your SuperBuild/External_python.cmake source folder

https://github.com/Slicer/Slicer/blob/master/SuperBuild/External_python.cmake#L56-L59

And the URL_MD5 to: "045fb3440219a1f6923fefdabde63342":

  set(python_SOURCE_DIR "${CMAKE_BINARY_DIR}/Python-2.7.15")

  ExternalProject_Add(python-source
    URL "https://www.python.org/ftp/python/2.7.15/Python-2.7.15.tgz"
    URL_MD5 "045fb3440219a1f6923fefdabde63342"
    DOWNLOAD_DIR ${CMAKE_BINARY_DIR}
    SOURCE_DIR ${python_SOURCE_DIR}
    CONFIGURE_COMMAND ""
    BUILD_COMMAND ""
    INSTALL_COMMAND ""
    )

And rebuild.

I am testing it too.

I tested it, and hitting this bug: https://github.com/python-cmake-buildsystem/python-cmake-buildsystem/issues/224

I am going to disable nis using this branch: https://github.com/phcerdan/python-cmake-buildsystem/commit/a0ba1dc557d870e625e4a03373f3fb2a9f42d9fb

My work in progress to update python is in this branch: https://github.com/phcerdan/Slicer/tree/update_python

I tested with 2.7.15, and it built fine. When I try to start Slicer I built, I get a segmentation fault, but that might be unrelated to the Python problem (I also got it earlier when I managed to build Slicer using the system Python installation):

When running SlicerApp-real in gdb:

$ cd Slicer-Superbuild-Release/Slicer-build/bin
$ gdb SlicerApp-real
(gdb) run

Starting program: /home/torquil/src/upstream/slicer/Slicer-Superbuild-Release/Slicer-build/bin/SlicerApp-real
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffce256700 (LWP 29316)]
[New Thread 0x7fffcd3af700 (LWP 29317)]

Thread 1 "SlicerApp-real" received signal SIGSEGV, Segmentation fault.
__strcmp_sse2_unaligned () at /build/glibc-hBZSf0/glibc-2.27/string/../sysdeps/x86_64/multiarch/strcmp-sse2-unaligned.S:31
31 /build/glibc-hBZSf0/glibc-2.27/string/../sysdeps/x86_64/multiarch/strcmp-sse2-unaligned.S: No such file or directory.
(gdb)

But I can report this in a different bug report, unless you immediately know what causes it? :-) At least the building works for me now.

This will be fixed as soon as the following PR is integrated: https://github.com/python-cmake-buildsystem/python-cmake-buildsystem/pull/263

Fixed in r28743
See http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=28743