mctc-lib: fix openmp cores in checkPhase

Changed files
+4
pkgs
by-name
mc
mctc-lib
+4
pkgs/by-name/mc/mctc-lib/package.nix
···
doCheck = true;
+
preCheck = ''
+
export OMP_NUM_THREADS=2
+
'';
+
postPatch = ''
patchShebangs --build config/install-mod.py
'';