[ccache] Ccache version 4.2.1 has been released

[Joel Rosdahl]

Ccache version 4.2.1 is now available. Release archives can be found here:

    https://ccache.dev/download.html

Bug fixes:

  - Ccache now only “dup2”s stderr into “$UNCACHED_ERR_FD” for calls to the
    preprocessor/compiler. This works around a complex bug in interaction with
    GNU Make, LTO linking and the Linux PTY driver.

  - Fixed detection of color diagnostics usage when using “-Xclang
    -fcolor-diagnostics” options.

  - The “-frecord-gcc-switches” compiler option is now handled correctly to
    avoid false positive cache hits.

  - Made it possible for per-compilation debug log files to be written in most
    argument processing error scenarios. Previously, ccache would only write
    debug log files if the argument processing phase was successful.

  - Made ccache bail out on too hard Clang option “-gen-cdb-fragment-path”.

  - The “run_second_cpp” made is now enforced on macOS if “-g” is used since
    newer Clang versions on macOS produce different debug information when
    compiling preprocessed code.

  - Made ccache only reject “-f(no-)color-diagnostics” for a known GCC
    compiler. This fixes a problem when using said option with Clang on macOS.

  - Implemented a better “stat”/“lstat” wrapper function for Windows.

  - Fixed a bug where ccache could return stale cache results on Windows.

  - Fixed handling of long command lines on Windows.

Portability and build improvements:

  - Build configuration scripts now probe for atomic increment as well. This
    fixes a linking error on Sparc.

  - An existing CMake log message level is now used when warning about not
    finding asciidoc.

  - Added support for building ccache with xlclang++ on AIX 7.2.

  - Fixed assertion in the "Debug option" test.

  - Made build configuration skip using ccache when building with MSVC.

  - Upgraded to doctest 2.4.6. This fixes a build error with glibc >= 2.34.

Documentation:

  - Fixed markup of “compiler_type” value "other".

  - Fixed markup of “debug_dir” documentation.

  - Fixed references to the “extra_files_to_hash” configuration option.

Contributors (in alphabetical order) to this release:

  - Abubakar Nur Khalil
  - Aleksander Salwa
  - Evangelos Foutras
  - Joel Rosdahl
  - Jon Petrissans
  - Nicholas Hutchinson
  - Pawel Krysiak
  - Sergei Trofimovich
  - Thomas Otto

Thanks!

-- Joel