Re: [PATCH v2] pager: fix crash when pager program doesn't exist

Ævar Arnfjörð Bjarmason [off-list ref] writes:

We then use that to check if we set it up ourselves and skip setting it
up, but any other program invoked by us will be fooled by
GIT_PAGER_IN_USE=true. Maybe that's intentional,...

I think there is no other reason than to ensure subprocesses we
spawn (be it git or somebody else that will later spawn git) are
affected; otherwise a global variable in environment.c would have
sufficed.

Presumably we can invoke N git <something>, where those <something> have
different pager.<something> config...

A tangent, but pager.<cmd> should be renamed/transitioned to
pager.<cmd>.program, I would think.  Not that we allow characters
that are unsafe in the configuration variable names (like dot ".")
in the names of Git subcommands right now, but any name that is
taken from an unbounded set should not appear anywhere but the
second level of a three-level configuration variable name.