Include time.h explicitly

[aroningruber]

Pull Request Description

This pull request addresses a build issue related to the use of clock_t and CLOCKS_PER_SEC in the find_intervals_stack functions, which appear in the following files:

• fintervaldb.c (Lines 1196-1200)
• intervaldb.c (Lines 1220-1224)

The existence of these symbols is implicitly assumed, which can cause the build to fail in environments where time.h is not automatically included (#56).

Changes Made

• Added an explicit #include <time.h> directive to defaults.h to ensure clock_t and CLOCKS_PER_SEC are always defined.

Issue Fixed

• Fixes Windows build fails for CPython 3.13 #56

[endrebak]

I think these were leftovers from some benchmarking. I can just delete these references.

[endrebak]

Thanks for making me aware of this bw