fix for crash on Windows

[mamert]

SIGINT is n/a on Windows, with no easy replacement, hence the added condition

[codecov[bot]]

Codecov Report

Merging #202 (a998ae5) into master (0da95d1) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #202   +/-   ##
=======================================
  Coverage   98.79%   98.80%           
=======================================
  Files           1        1           
  Lines         249      250    +1     
=======================================
+ Hits          246      247    +1     
  Misses          3        3           

Impacted Files	Coverage Δ
mptools/_mptools.py	98.80% <100.00%> (+<0.01%)	:arrow_up:

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