cpython: have powerpc64le use "ppc64le" to follow PEP600

The PEP600 standard gives Python's naming scheme for various
architectures; it follows the convention which was in use by Fedora in
2014.  According to PEP600, the architecture name for Power PC is
`ppc64le`, not `powerpc64le`.  This is also how python3 declares its
"supported wheels" under Debian on PowerPC, as checked with `pip debug
--verbose`

  $ pip debug --verbose | grep powerpc
  $ pip debug --verbose | grep ppc | head
  cp39-cp39-manylinux_2_31_ppc64le
  cp39-cp39-manylinux_2_30_ppc64le
  cp39-cp39-manylinux_2_29_ppc64le
  cp39-cp39-manylinux_2_28_ppc64le
  cp39-cp39-manylinux_2_27_ppc64le
  cp39-cp39-manylinux_2_26_ppc64le
  cp39-cp39-manylinux_2_25_ppc64le
  cp39-cp39-manylinux_2_24_ppc64le
  cp39-cp39-manylinux_2_23_ppc64le

Let's adjust the `pythonHostPlatform` expression in
cpython/default.nix to pass the architecture using the naming scheme
Python expects.

Verified on a Raptor Computing Systems Talos II.  Without this commit,
PyQt5 fails to build, failing with "unsupported wheel".  With this
commit, it builds successfully.

0 files changed, 0 insertions, 0 deletions