Issue a warning when casting a GIL-requiring function into a nogil function (which breaks GIL validation).
Closes GH-2879.

Fix reference in docs

See #2879.

Refactor parsing function in code coverage plugin to split the actual parsing code from the lookup code.

Exclude non-executable lines from coverage analysis (anything that does not generate a line trace call).

GH-1461: Include the signature line of cdef functions in the import-time line tracing and coverage report.

GH-1461: Include the signature line of cdef functions in the import-time line tracing and coverage report.

Allow condition in GILStatNode

Prevent the time stamps in the test runner from being captured together with the output of the C compiler.

Disable the new compiler warning about ambiguous exception return values when the function is external (and therefore possibly not under the control of the user).

Faster absolute reimports

When running a single test for multiple language levels, make sure they end up in different directories to prevent overwriting each other.

GH-2854: Implement CPython's safety guard against concurrent module initialisations during the import.