Improvements:
- Support and testing for clang 19 and gcc 14
- Partial support for thread sanitizer
- Dramatically simplified build system
- Removed numerous unused build configs
- Fixed a minor performance regression from the last release
- Removed hand-imlemented atomics in favor of C11 atomics and existing intrinsics
- Removed unmaintained support for eurekas
- Removed unmaintained support for distributed Qthreads
- Removed various unmaintained debugging and profiling code paths
- Dropped support for numerous compilers that no are no longer available
- Dropped support for various unmaintained architectures like Tilera, Itanium, Alpha, MIPS, and Sparc
- Dropped support for various OS configs that we don't test like Solaris, HPUX, and AIX
- Removed several unmaintained/untested threadqueue and topology detection options