fix(setup): force rebuilding Cython files (#1468)

Always force rebuilding Cython files to make sure we build for the right Python
version.
This allows to remove the hack we had in tox.ini and makes sure that when
building from a sdist, the .c files are generated with the right Python version.

Fixes #1461

Co-authored-by: Brett Langdon <[email protected]>

Author: 2 people

setup.py

@@ -172,6 +172,7 @@ def get_exts_for(name):
                 "PY_MINOR_VERSION": sys.version_info.minor,
                 "PY_MICRO_VERSION": sys.version_info.micro,
             },
+            force=True,
         )
         + get_exts_for("wrapt")
         + get_exts_for("psutil"),

tox.ini

@@ -158,8 +158,7 @@ isolated_build = true
 #      meaning running on py3.x will fail
 #      https://stackoverflow.com/questions/57459123/why-do-i-need-to-run-tox-twice-to-test-a-python-package-with-c-extension
 whitelist_externals=rm
-commands_pre=rm -f ddtrace/profiling/_build.c ddtrace/profiling/collector/stack.c ddtrace/profiling/collector/_traceback.c ddtrace/internal/_rand.c
-             {envpython} {toxinidir}/setup.py develop
+commands_pre={envpython} {toxinidir}/setup.py develop
 usedevelop =
   # do not use develop mode with celery as running multiple python versions within
   # same job will cause problem for tests that use ddtrace-run