I'm OK with removing this part of the synopsis instead. I'd vote that we remove *all* of the C++20-but-not-yet-implemented chrono parts in the synopsis then, such as time zone database, time zones, exception classes, parsing, etc (basically all of C++20 chrono stuff mentioned in the synopsis).
Guard with TEST_HAS_NO_EXCEPTIONS
Address Arthur's feedback
I have reverted and will fix it.
Fix patch format
there is some compiler crash after the patch https://lab.llvm.org/buildbot/#/builders/77/builds/10553/steps/10/logs/stdio
Move the entire to_char floating-point implementation to the dylib
I guess a downside of this solution, is that if an i686 sysroot exists next to the clang binary, it becomes practically impossible to test codegen differences when you run it with various -target iX86-w64-mingw32 options, as they'd all be corrected back to i686. (This wouldn't be an issue if the autodetection was done in computeTargetTriple only when the -m32/-m64 options are used though.)