fuzz: use a variable to allow specifying python-config to use Eventually we should probably default this to just `python-config` and have the oss-fuzz build.sh script specify the sanpy python-config, but for now this lets us make progress. Differential Revision: https://phab.mercurial-scm.org/D7563

fuzz: suppress deprecated-register warnings in our compile These come from the Python.h headers still using the `register` keyword and our use of C++17. I think this will go away when we're using Python 3 for our fuzzing, but that can come later. Differential Revision: https://phab.mercurial-scm.org/D7562

fuzz: follow modern guidelines and use LIB_FUZZING_ENGINE This will make our lives easier in an upcoming change, but it's also how we're supposed to set things up anyway. Differential Revision: https://phab.mercurial-scm.org/D7561

fuzz: always define LLVMFuzzerInitialize() even if we don't need it This will make it easier to test our fuzzers outside oss-fuzz. Differential Revision: https://phab.mercurial-scm.org/D7560

fuzz: remove debug prints from revlog_corpus.py Differential Revision: https://phab.mercurial-scm.org/D7559

fuzz: fix an unused result on getcwd() in pyutil clang was rightly complaining about this, so let's just fix it. Differential Revision: https://phab.mercurial-scm.org/D7558

upgraderepo: add a config option for parallel computation The option is put to use to compute new copy tracing side data in parallel. It use the multiprocessing module as it had the appropriate primitive for what we needed. Gregory Szorc had concerned on windows so we disabled it there. See inline comment for details on the parallel implementation.

upgrade-repo: colorize some of the output Having clear color for requirement added and removed is useful.