This option only affects absolute filenames that are found by
ffap-file-at-point in buffers with remote default directory.

The handling of relative filenames in above buffers remains
unchanged: ffap-file-at-point returns the relative filename,
which can be converted to a remote absolute filename by
subsequent callers (e.g. ffap) using expand-file-name.

* lisp/ffap.el (ffap-prefer-remote-file): New user option.
(ffap-file-exists-string): Add an optional argument to allow the
check of existence of absolute filename on the remote host.
(ffap-file-at-point): Always find remote files in remote context
if the new option is non-nil.
* test/lisp/ffap-tests.el (ffap-test-remote): Add a test.
* etc/NEWS: Announce the change.

This reverts commit ae46edff68e8d5729207ed849df83ecb039e11bb.
I mistakenly installed the wrong version of the patch for
bug#78925.

This option only affects absolute filenames that are found by
ffap-file-at-point in buffers with remote default directory.

The handling of relative filenames in above buffers remains
unchanged: ffap-file-at-point returns the relative filename,
which can be converted to a remote absolute filename by
subsequent callers (e.g. ffap) using expand-file-name.

* lisp/ffap.el (ffap-prefer-remote-file): New user option.
(ffap-file-exists-string): Add an optional argument to allow the
check of existence of absolute filename on the remote host.
(ffap-file-at-point): Always find remote files in remote context
if the new option is non-nil.
* test/lisp/ffap-tests.el (ffap-test-remote): Add a test.
* etc/NEWS: Announce the change.

* lisp/ffap.el (ffap-file-name-with-spaces): Doc fix.
(ffap-string-at-point): Don't reject '~foo/' and 'd:/bar' file
names when 'ffap-file-name-with-spaces' is non-nil.

* test/lisp/ffap-tests.el (ffap-test-with-spaces): Add tests, and
fix expected results to not strip Windows drive letters.

* test/lisp/ffap-tests.el (ffap-test-path-unix): Renamed from
'ffap-test-path'.
(ffap-test-path-portable): New test, which should work on all
systems.

This function is used so rarely that it's really best not to
preload it.

* lisp/ffap.el (ffap-url-regexp): Precompute.
(ffap-c-path): Use `ffap--c-path`.
(ffap--gcc-is-clang-p, ffap--c-path): Move and rename from subr.el's
* lisp/subr.el (internal--gcc-is-clang-p)
(internal--c-header-file-path): Move to ffap.el and rename.

* lisp/man.el (Man-header-file-path): Default to a new value that
delegates to ffap.
(Man-header-file-path): Obey that new value.

* lisp/emacs-lisp/ert-x.el (ert-gcc-is-clang-p): Use `ffap--gcc-is-clang-p`.

* test/lisp/ffap-tests.el (ffap-tests--c-path)
(ffap-tests--c-path/gcc-mocked, ffap-tests--c-path/clang-mocked):
Move and rename from `subr-tests.el`.
* test/lisp/subr-tests.el (subr-tests-internal--c-header-file-path)
(subr-tests-internal--c-header-file-path/gcc-mocked)
(subr-tests-internal--c-header-file-path/clang-mocked):
Move to `ffap-tests.el` and rename.

Run "TZ=UTC0 admin/update-copyright".

* test/lisp/ffap-tests.el (ffap-file-remote-p, ffap-machine-p):
New tests.