On Databricks, both Intel OMP (libiomp5 via MKL) and GNU OMP (libgomp
via scipy) are pre-loaded by the kernel before any user code runs.
KMP_DUPLICATE_LIB_OK set in Python is too late — the assertion fires
during runtime initialization.

JAMMA_NO_OPENMP=1 tells the compile scripts to skip OpenMP flags
entirely, producing single-threaded C extensions that avoid the
dual-runtime conflict. Still much faster than pure-Python fallback.