makedepend_file.SH: Add some sed edits for z/OS

[khwilliamson]

• This set of changes does not require a perldelta entry.

[jkeenan]

Does this p.r. have any interaction with #23402, currently pending?

[khwilliamson]

I expect not.

[tonycoz]

It looks reasonable to me, though I wonder why warnings are going to stdout, since this adds:

-e '/".*In file included from.*:/d' \'

and that test is typically from diagnostics.

I do expect some conflict with #23402 since that renamed makedepend_file.SH to makedependfile.SH