When `set!` is used to tie a recursove knot in a flattened linklet,
the expander can recognize that pattern and not complain that a
mutable variable might be shared across places. Improving that
inference means fewer `++global-ok` flags in Makefiles.
This commit also avoids single-quote as an escaping form in a
makefile, which doesn't work with nmake on Windows.
Continue to build the bundled-with-Chez zlib and lz4 by default, but
support `--enable-libz` and `--enable-liblz4`, and turn those on when
the Chez Scheme directory doesn't have bundled versions. That should
make things build right for distributions where repackaging
dependencies is disallowed or discouraged.
The Chez Scheme build process now create an archive instead of linking
"kernel.o". Adjust the Racket CS build to use archives instead of
"kernel.o".
Also, modernize the Racket build's use of `ar`. Using the flags `rc` by
default (instead of `ruv`) should avoid the need for `nicear`.
If GUN ar is configured for deterministic mode by default, then
ar: `u' modifier ignored since `D' is the default (see `U')
prints. Suppress that to avoid stderr output.
Checking for directories when searching for a collection can be
especially slow with the Windows filesystem, but Windows also supports
filesystem-change events. So, cache information about the existence of
paths, relying on filesystem-change events to detect with the cache is
out of date.
Related to racket/drracket#281
The prompt installed for an escape continuation or continuation
barrier is never used to delimit a captured continuation, so the
return from the continuatiton can be streamlined slightly.
The benefit is very small (but detectable in the macro expander's use
of barriers). There's an opportunity to use `call/1cc` instead of
`call/cc`, but that change does seem to help --- neither Chez Scheme's
current `call/1cc` nor the opportunistic variant of `call/cc` use to
implement continuation attachments.
Reducing external-event polling exposed a problem with fd semaphore
checking, where the check before sleeping didn't abandon the sleep if
an fd semaphore was posted.
Also, fix a bug with interrupted network address lookup.
