Python version misselected and Python 3.5 install failure

[Martin Husemann <martin%duskware.de@localhost>]

What did I do wrong?

===> Installing dependencies for iso-codes-3.68
==========================================================================
The following variables will affect the build process of this package,
iso-codes-3.68.  Their current value is shown below:

        * PYTHON_VERSION_DEFAULT = 27

Based on these variables, the following variables have been set:

        * PYPACKAGE = python35

You may want to abort the process now with CTRL-C and change their value
before continuing.  Be sure to run `/usr/bin/make clean' after
the changes.
==========================================================================

why 3.5?

and then building that python version fails:

INFO: [subst.mk:unwrap] Nothing changed in ./Misc/python.pc.
===> Installing for python35-3.5.1nb2
=> Generating pre-install file lists
python: not-found! cannot run Tools/scripts/generate_opcode_h.py ./Tools/scripts/generate_opcode_h.py ./Lib/opc
ode.py ./Include/opcode.h
Creating directory /usr/pkg/bin
Creating directory /usr/pkg/lib
if test "no-framework" = "no-framework" ; then  /usr/bin/install -c -s -o root -g wheel -m 755 python /ssd/pkgo
bj/lang/python35/work/.destdir/usr/pkg/bin/python3.5;  else  /usr/bin/install -c -s -o root -g wheel -m 755 -s 
Mac/pythonw /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/bin/python3.5;  fi
if test "3.5" != "3.5"; then  if test -f /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/bin/python3.5 -o -h /s
sd/pkgobj/lang/python35/work/.destdir/usr/pkg/bin/python3.5;  then rm -f /ssd/pkgobj/lang/python35/work/.destdi
r/usr/pkg/bin/python3.5;  fi;  (cd /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/bin; /bin/ln python3.5 pytho
n3.5);  fi
if test -f libpython3.5.so && test "no-framework" = "no-framework" ; then  if test -n "" ; then  /usr/bin/insta
ll -c -o root -g wheel -m 555  /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/bin;  else  /usr/bin/install -c 
-o root -g wheel -m 555 libpython3.5.so /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/lib/libpython3.5.so.1.0
;  if test libpython3.5.so != libpython3.5.so.1.0; then  (cd /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/li
b; /bin/ln -sf libpython3.5.so.1.0 libpython3.5.so)  fi  fi;  if test -n "libpython3.so"; then  /usr/bin/instal
l -c -o root -g wheel -m 555 libpython3.so /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/lib/libpython3.so;  
fi;  elif test -f libpython3.5.so.1.0; then  /usr/bin/install -c -o root -g wheel -m 555 libpython3.5.so.1.0 /s
sd/pkgobj/lang/python35/work/.destdir/usr/pkg/lib;  fi
if test "x" != "x" ; then  rm -f /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/binpython3.5-32;  lipo   -outp
ut /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/bin/python3.5-32  /ssd/pkgobj/lang/python35/work/.destdir/usr/pkg/bin/python3.5;  fi
Fatal Python error: Py_Initialize: can't initialize sys standard streams
OSError: [Errno 9] Bad file descriptor

Current thread 0x00007bf0b64cb800 (most recent call first):
[1]   Abort trap (core dumped) LD_LIBRARY_PATH=...
*** Error code 134


This is on NetBSD amd64 -current, pkgsrc current as of yesterday.
No relevant /etc/mk.conf settings (a few liceneses, and PKG_OPTIONS for
other pkgs); PKG_DEVELOPER=yes


Any hints?

Martin