kbuild: mksysmap: Build regression for next-20240604

[Jon Hunter]

Hi Kent,

Since next-20240604 I noticed a build regression in our farm builders
and I am seeing the following error ...

/usr/bin/env: invalid option -- 'S'
Try '/usr/bin/env --help' for more information.

These builders have an older version of 'env' that do not support the
'-S' argument and so your change [0] is breaking the for these
machines. I did not see your patch on any list and found it on your
bcachefs tree [1]. So not clear if this has been reviewed and if this
is trying to fix some related to Masahiro change [2]?

It is also not clear what the minimum version of 'env' is supported
for building the linux kernel, but these builders have been building
the kernel fine for years.

Thanks
Jon

[0] https://evilpiepirate.org/git/bcachefs.git/commit/?h=for-next&id=973eca8db5570dd0c3f2b3190867138cc446eb3b
[1] https://evilpiepirate.org/git/bcachefs.git/log/?h=for-next
[2] https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/commit/?h=kbuild&id=b18b047002b7d3b19d9fb905c1bd2a214016c153