bug#71336: CI failure

[Bruno Haible]

Hi Ileana,

The CI on GitHub (master branch) failed to create the tarball, unlike last week.
The cause is this failure of a maint.mk check:

...
immutable_NEWS
maint.mk: you have modified old NEWS
make[1]: *** [maint.mk:1257: sc_immutable_NEWS] Error 1
make[1]: Leaving directory '/home/runner/work/ci-check/ci-check/libtool'
make: *** [Makefile:1868: distcheck] Error 1

In order to fix this, I see two options:
  - either change the contents of NEWS,
  - or disable the sc_immutable_NEWS rule (by editing cfg.mk).

Bruno