os400: getpeername() and getsockname() return ebcdic AF_UNIX sockaddr,

[monnerat]

As libcurl now uses these 2 system functions, wrappers are needed on os400
to convert returned AF_UNIX sockaddrs to ascii.

This is a follow-up to commit 7fb54ef.
See also #4037.

I would appreciate a compilation test prior to commit, maybe by @jonrumsey. Thanks in advance.

[bagder]

@monnerat this doesn't seem to get any other OS/400 users to review. The question is then mostly if you think we should land this anyway since it is the right way and probably right, or if we should just not do it and wait for the problem to hurt some users who can work on a fix then?

[jonrumsey]

@monnerat , @bagder - Apologies, I missed the original mention notification. I successfully compiled the proposed changes this morning on OS400 V7R2M0.

[monnerat]

@bagder: What I am sure is the values returned by these 2 system functions will appear to curl as garbage when applied to unix sockets ! the commit is supposed to fix that.
@jonrumsey: many thanks for confirming it compiles. I will push to master in a few minutes.