Issue #27659: use -Werror=implicit-function-declaration when possible (GCC and
Clang, but it depends on the compiler version).

Patch written by Chi Hsuan Yen.

Issue #29362: Catch a crash of a worker process as a normal failure and
continue to run next tests. It allows to get the usual test summary: single
line result (OK/FAIL), total duration, etc.

_PyArg_NoPositional() now are macros.

Patch by Ryan Gonzalez.

the match object.  Based on patch by WGH.

the match object.  Based on patch by WGH.

the match object.  Based on patch by WGH.

Patch by Chi Hsuan Yen.

Decreased density gives better collision statistics (average of 2.5 probes in a
full table versus 3.0 previously) and fewer occurences of starting a second
possibly overlapping sequence of 10 linear probes.  Makes resizes a little more
frequent but each with less work (fewer insertions and fewer collisions).

Based on patch by Georg Brandl.

Original patch by Georg Brandl.

using PySlice_GetIndicesEx() in debug builds.

using PySlice_GetIndicesEx() in debug builds.