…x, and longonly

This reverts commit 223b3d1.

Fixes #1851

gcc 15.2.1 20250813 complains "address of automatic variable can
escape to `musttail` call" from `-Wmaybe-musttail-local-addr`,
and guaranteeing tail-call optimization cross-platform is more
trouble than it's worth.

Fixes #1855

since they may call `isatty` which can change `errno`

Fixes #1857

…op` builds (#1859)

This was the only RPN case to not assign a deliberate value
in all possible branches.

Fixes #1858

Dot-only names could also trip an assertion in `make develop`
when used as labels

…1867)

- ID numbers (for fstack nodes, sections, symbols, patches, etc)
  might be too large for their associated collection
- Enum values might be invalid
- Bank values might be out of range for their section types

Commit 63a911e switched
to `-std=c++20` since at the time we required GCC 10 or higher.

Commit d5ce532 partially reverted
to `-std=c++2a` since we once again support GCC 9, which did not
yet handle `std=c++20`.

…rs (#1964)

)

This fixes an error from using Cygwin's git in checkout's post-job cleanup

This will let us use C++20 features that GCC 9's experimental
C++20 support did not yet cover, such as "concepts".

This reverts some commits:
- 6bcd79b
- d5ce532
- 728d148

…entinel

The `errorNoTrace` case for the empty-string sentinel was unreachable,
so we can just have a `fatalNoTrace` error right away.

…1968)

…elop`

The Bison-generated parser skeleton otherwise triggers this warning
with Apple clang++ for `yynerrs_`.

…or `RPNCommand`s

…armaps, etc) (#1980)

…Content` (#1981)

Instead of reading 64 characters at a time into a rolling buffer
as `shiftChar()` is called, we read 8192 characters at a time into
a complete buffer before any `peek()`/`shiftChar()` operations.

Some test cases need CRLF line endings checked out even on Unix.
Also some source files had inadvertently contained CR bytes.

A fresh clone showed a diff even without any bytes changed.

This avoids constructing temporary `std::string` objects on lookup

- Fix logic for color set comparison (which affects sorting them)
- Prune color sets which are proper subsets of newly-encountered ones
  (a comment implied we were already doing this, but we weren't)
- Add more verbose logging to debug this behavior