CONTOUR is KO on OSX on x86 since circa one year

[alaingdl]

Since ~ March 2023, on two Mac with processor x86, CONTOUR is not OK : no contour lines plotted on contour, findgen(12,12)

I go back till Version 1.0.2 Git and same problem.

(I cannot compile nowadays the current 1.1 version on those Mac due to troubles related to Xcode 😞 :)

This problem with CONTOUR don't exist on Mac running on proc. M2

Concerning the testability of that king of problems, I suspect we can count the number of black & with pixels (we had such discussion with @GillesDuvert long time ago)