Warning when using SymPy with multiple files

[JCGoran]

When running NMODL on multiple mod files (such as nmodl file1.mod file2.mod ...) with SymPy enabled, a cryptic warning appears:

context.c:56: warning: mpd_setminalloc: ignoring request to set MPD_MINALLOC a second time

From this SO answer it seems the culprit is this line in cPython.

Possible solutions:

1. init the interpreter once, at the beginning of the program, and then close it at the very end
2. use something like Py_IsInitialized to check if the interpreter is running (part of stable ABI). This also needs the Python.h header

[1uc]

Third option, only allow one MOD file at a time.