I reverted 3498c642f4e83f3d8e2214654c0fa8e0d51cebe5 and tried to build cython and numpy an it fails for me still:

> git log

commit 17e024a1a999f96fee52e99bd4587da383647993 (HEAD -> master)
Author: Pablo Galindo <pablogsal@gmail.com>
Date:   Sat Jun 15 10:16:52 2019 +0100

    revert "bpo-37213: Handle negative line deltas correctly in the peephole optimizer (GH-13969)"

    This reverts commit 3498c642f4e83f3d8e2214654c0fa8e0d51cebe5.

commit 7efc526e5cfb929a79c192ac2dcf7eb78d3a4401 (upstream/master, upstream/HEAD)
Author: Victor Stinner <vstinner@redhat.com>
Date:   Sat Jun 15 03:24:41 2019 +0200

    bpo-36707: Document "m" removal from sys.abiflags (GH-14090)


❯ ~/github/cpython/python.exe -m pip install . --user
/Users/pgalindo3/.local/lib/python3.9/site-packages/pip/_vendor/html5lib/_trie/_base.py:3: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3,and in 3.9 it will stop working
  from collections import Mapping
Looking in indexes: http://localhost:3141/pablogsal/local/+simple/
Processing /Users/pgalindo3/github/cython
Installing collected packages: Cython
  Running setup.py install for Cython ... done
Successfully installed Cython-3.0a0

❯ ~/github/cpython/python.exe -m pip install . --user
    Processing numpy/random/dsfmt.pyx
    Traceback (most recent call last):
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/tools/cythonize.py", line 243, in <module>
        main()
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/tools/cythonize.py", line 239, in main
        find_process_files(root_dir)
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/tools/cythonize.py", line 230, in find_process_files
        process(root_dir, fromfile, tofile, function, hash_db)
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/tools/cythonize.py", line 196, in process
        processor_function(fromfile, tofile)
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/tools/cythonize.py", line 85, in process_pyx
        subprocess.check_call(
      File "/Users/pgalindo3/github/cpython/Lib/subprocess.py", line 348, in check_call
        raise CalledProcessError(retcode, cmd)
    subprocess.CalledProcessError: Command '['/Users/pgalindo3/github/cpython/python.exe', '-m', 'cython', '-3', '--fast-fail', '-o', 'dsfmt.c', 'dsfmt.pyx']' returned non-zero exit status 1.
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/setup.py", line 443, in <module>
        setup_package()
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/setup.py", line 426, in setup_package
        generate_cython()
      File "/private/var/folders/sw/ml9tlhsx7hd7sdqpnlzhrxxh0000gr/T/pip-req-build-1nbv5hs2/setup.py", line 234, in generate_cython
        raise RuntimeError("Running cythonize failed!")
    RuntimeError: Running cythonize failed!