make site: fix for SRC_CATALOG mode

In SRC_CATALOG mode, there's not a separate "native" directory.
ffi/unsafe win32: fix inefficiency in call-in-orig-thread mode

The problem made simultaneous rendering of "plot" and "math"
documentation about 10 times slower than it should be.
check result of mprotect()
try to fix module-caching test
win32: reduce allocation in the scheduler

It's not clear that the changes affect anything in practice,
but they avoid unnecessary allocation and quadratic behavior
in principle.
module caching: ensure consistency of directory paths

Use `path->directory-path` to normalize directory paths and
increase use of the cache.
treat OS page manager (especially Linux) more gently

Batch up mprotect() calls when cleaning up a place. Hopefully,
this will avoid ENOMEM errors from mprotect() on DrDr's build.
avoid compiler warnings
optimizer: fix bug

Repair a typo in b0f4a32049; thanks to Blake Johnson.
bump version
string-normalize-...: fix memcpy that should be memmove
Fix typechecking of (syntax ...) expressions

The type is
  (Syntaxof the-type-of-the-result-of-syntax-e), not
  (Syntaxof the-type-of-the-result-of-syntax->datum)

Closes PR 14561
Adjust types for stx-map and syntax->list

These types need to be adjusted to match the types that
are now produced for syntax datums due to the previous
commit.
Fixes and additions for some GUI class types
avoid compiler warnings
fix docs for `image`
unzip: Handle non-seekable input ports.

Before this commit:
  - unzip would attempt to seek the input port via file-position in some cases

After this commit:
  - unzip reads and discards bytes as needed to skip forward
Handle data descriptor signatures in file/unzip

http://www.pkware.com/documents/casestudies/APPNOTE.TXT specifies that a data
descriptor signature may be placed after the compressed data and before the
data descriptor. file/unzip now handles this case.