Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

env: Fix crash when -S string is not empty but no operand follows.

split_spaces() set argc in main() incorrectly, which caused trouble for
getopt().

Examples:
env -S '\c'
env -S -i

PR: 197769
MFC after: 1 week

env: Fix testsuite for additional variables set by sh.

MFC after: 1 week

Correct one regression test (which was expected an incorrect answer), and
add a few more tests. This matches bug fixes recently committed to 'env'.

Upgrade these regression tests to track recent changes to `env'.

Approved by: re (blanket `env')

Add a suite of regression tests for all the recent changes to `env',
using my own script to handle it. I wrote my own partially because
of all the quoting-issues involved with testing what I wanted to test,
and partially because this lets me commit one script and one data file,
instead of one-file-per-regression-test.

This suite was good enough for my initial testing (and it did help me
find a few bugs that would have otherwise been missed). I'm not sure
how well it will work in general use, but I figured I might as well
commit it. It won't *hurt* to have it available. At the worst, people
can just ignore it.

Approved by: re (blanket `env')