Turns out that the FreeBSD ports Makefiles install programs and scripts with 0555 by default,
i.e. without write permissions.
This broke the install-exec-hook unless building as root.
Unfortunately, this also broke the Poudriere builds at the FreeBSD build servers.
See https://pkg-status.freebsd.org/package19/data/141amd64-default-build-as-user/aa1f9b124e36/logs/errors/sciteco-curses-2.2.0.log

* This goes into session.vcs as well.
* `fossil info` does not allow printing only the local-root property, so we have to do
  some parsing afterwards.

* In fact, since SVN has --no-newline, this is even simpler than on Git and Mercurial.
* This requires at least Subversion v1.9 (2015, so should be safe).

* Turns out that on SunOS/OmniOS the ncurses port does not ship with
  a ncursesw pkg-config file, but the ncurses file is for a version,
  that does contain widechar support as well.
* Instead of adding yet another recursive PKG_CHECK_MODULES() call,
  we now use the AX_WITH_CURSES() macro, which is probably more robust.
  This should at least fix ./configure on OmniOS.
* It also adds a number of feature C macros, that could be useful to
  check in the future.
* At the moment, we strive to support all X/Open-compatible Curses
  libraries, but both enhanced and color functions are required.
  Therefore plain SVr4 Curses is not supported.
* source: https://www.gnu.org/software/autoconf-archive/ax_with_curses.html

* The previous convention of !* ... *! are now true block comments,
  i.e. they are parsed faster, don't spam the goto table and allow
  embedding of exclamation marks - only "*!" terminates the comment.
* It is therefore now forbidden to have goto labels beginning with "*".
* Also support "!!" to introduce EOL comments (like C++'s //).
  This disallows empty labels, but they weren't useful anyway.
  This is the shortest way to begin a comment.
* All comment labels have been converted to true comments, to ensure
  that syntax highlighting works correctly.
  EOL comments are used for single line commented-out code, since it's
  easiest to uncomment - you don't have to jump to the line end.
  This is a pure convention / coding style.
  Other people might do it differently.
* It's of course still possible to abuse goto labels as comments
  as TECO did for ages.
* In lexing / syntax highlighting, labels and comments are highlighted differently.
* When syntax highlighting, a single "!" will first be highlighted as a label
  since it's not yet unambiguous. Once you type the second character (* or !),
  the first character is retroactively styled as a comment as well.

* They are used at runtime only by the GTK port.
* Their existence can cause problems if OS-specific build systems
  have to clean these files from the staging directory afterwards.
  This was the case on FreeBSD where the committer refused to remove
  these files after installation.
  In the official FreeBSD port, we therefore currently ship the
  PNG icons unnecessarily.
* They are now installed and shipped only on GTK builds.

This is not done automatically when building ports.
The FreeBSD binaries were thus the only ones without LTO.
We should prefer WITH_LTO, even once we add something like --enable-lto,
as WITH_LTO enables Clang-specific ThinLTO support.