docs: def c(source, libraries=[]):
      r"""
      >>> c('int add(int a, int b) {return a + b;}').add(40, 2)
      42
      >>> sqrt = c('''
      ... #include <math.h>
      ... double _sqrt(double x) {return sqrt(x);}
      ... ''', ['m'])._sqrt
      >>> sqrt.restype = ctypes.c_double
      >>> sqrt(ctypes.c_double(400.0))
      20.0
      """
      path = _cc_build_shared_lib(source, '.c', libraries)
      return ctypes.cdll.LoadLibrary(path)