- Twine, StringRef, Format, and NativeFormatting have been removed
- Logging now uses fmtlib style formatting
- Nearly all uses of wpi::outs/errs have been replaced with fmt::print() or
std::puts()/std::fputs() (for unformatted strings).
- A wpi/fmt/raw_ostream.h header has been added to enable
fmt::print() with wpi::raw_ostream
This can be dangerous as it refers to a temporary, and GCC 9.0 warns about
its use. Instead add std::initializer_list overloads to common places it
was used in an initializer_list sense.
