Re: make check fails? (emacs-26.1 w/modules)

[Greg Minshall <minshall@acm.org>]

here's a possibility, but i don't really understand the plumbing.

i wonder if it's the case that in src/emacs-module.c, the member
"pending_non_local_exit" of "struct emacs_env_private" should be marked
"volatile".  my sense is that it is, among other things, what links the
lower (signal/interrupt context) and upper (thread context) halves of
emacs/emacs-module (though i can't really see it).

if so, probably also the members "non_local_exit_{symbol,data}" should
be similarly marked.

[marking pending_non_local_exit volatile *does* result in (what appears
to be) good optimization; this is hardly surprising, though, as probably
if the optimizer saw even "volatile int i;" as a member of the struct,
it would back way off any code around it.  if this is what is causing
the bad optimization, it seems likely to still be a compiler.]

cheers, Greg

ps -- it's been years, decades, since i've had occasion to think of
"volatile", and possiblly the technology of such "attributes" has
advanced in the meantime.