$ENV handling depends on defined(linux), why??

[Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx>]

I was looking at this bit:

        if (
#ifndef linux
                getuid() == geteuid() && getgid() == getegid() &&
#endif
                iflag
        ) {
                if ((shinit = lookupvar("ENV")) != NULL && *shinit != '\0') {
                        read_profile(shinit);
                }
        }

thinking "condition order is wrong, if !iflag, calling getuid()
is pointless, we waste 4 syscalls" but then I noticed
"#ifndef linux". So, the inefficiency is not biting me, a linux user...

...but wait. (1) this check says "if we are setuid and run by non-root,
do not source $ENV". Who in their right mind would have a *setuid*
shell executable on any system where security matters?
IOW: this code is pointless anyway even for non-linux users.
And
(2) If there is some sort of standard language somewhere which says
this logic has to exist, then why we don't do this on linux?

git history shows it was there in initial import.

I propose to delete entire #ifndef/#endif block. It's likely wrong.

Alternatively, move "iflag" above "getuid() == geteuid()" checks.