Reverse order of environ tables under bash on VMS.

The default for populating %ENV on VMS is from logical names
first and the CRTL environ array second unless overridden by
setting PERL_ENV_TABLES. That's a reasonable default for DCL,
but not quite right when running under bash as exports under bash
might end up hidden behind logical names.  So reverse the default
order when GNV$UNIX_SHELL is set.

Also stop mentioning that setenv() may not be present in the CRTL
since it is present for VMS versions 7.0 and later and those are
the only ones we support.
PATCH: [perl #122460] Regression with (?{})(?=...) and pos

The commit that really broke this was
a0dd42312a1f26356d2fdf49656e45b77c2cefb5.  The blamed commit fixed some
typos that kept the earlier bad commit from having an effect.

Zero-length assertions, such as (?=...) obviously can match an empty
string.  The bad commit wrongly removed a setting of a flag to that
effect.  I didn't realize the implications at the time, thinking that
the newly-corrected AND logical operations would correctly set things
up, and that the previous code had been a workaround for the buggy AND.
The problem is that there is an overriding context such that whatever
the AND result, since this is in a 0-length assertion, the result will
match the empty string.  Thus it now differs from the pre-bad-commit
code which set to match the empty string only sometimes.  I'm pretty
sure it should be 'always'.  If I'm wrong, it doesn't mean a bug, but
only that an optimisation that could take place won't.
regcomp.c: White space only

Update line to coding standards so that the "{" is in the proper
position