OS X still uses clang-14, which lacks sufficient std::ranges support for
recent Rebirth changes.
- Rewrite uses of std::ranges::SYMBOL to ranges::SYMBOL
- Add a stub header that, on gcc, provides for each SYMBOL a statement
`using std::ranges::SYMBOL;`, to delegate back to the standard library
implementation.
- On clang, define a minimal implementation of the required symbols,
without constraint enforcement. Compile-testing with gcc will catch
constraint violations.
Once OS X clang ships a standard library with the required features,
this stub header will be removed and the uses changed back to their full
names.
std::ranges::find_if permits use of a sentinel instead of a full
iterator, and supports std::ranges::find as an alternative to certain
simple uses of std::find_if.
Where possible, use the form that takes a range, rather than the form
that takes two iterators.
Add a declared, but not defined, default constructor for
self_return_iterator to satisfy the standard library's concept
`semiregular`, which insists that sentinels be default-constructible,
even for those functions that never need to do so.
Add a defined, but unused, operator++(postfix) for zip_iterator to
satisfy a standard library concept for `forward_iterator`.
For each link given as http://, verify that the site is accessible over
https:// and, if so, switch to it. These domains were converted:
* llvm.org
* clang.llvm.org
* en.cppreference.com
* www.dxx-rebirth.com
* www.libsdl.org
* www.scons.org
<=gcc-5 with -Wold-style-cast warn when expansions of SDL macro
CD_INDRIVE produce an old style cast, even though the cast comes from a
system header. Undefine it and define an equivalent that uses a C++
cast, so that uses do not provoke a warning.