Fix segfault when complex double matrix calls ZGETRF (bug #45577). * CMatrix.cc (finverse, determinant, rcond, fsolve): Calculate norm of matrix and if it is NaN, skip calling ZGETRF in LAPACK and set info to non-zero value to signal an error.

function x = varg_nest (varargin)
  x = abs (f (-5)) + g;

  function x = f (varargin)
    x = abs (varargin{1});
  endfunction

  function x = g
    x = abs (varargin{1});
  endfunction
endfunction