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.

# fA.m
function y = fA (x, f)
  global gfun
  if nargin < 2
    y = fA (x, gfun);
  else
    w = feval (f, x);
    y = feval (@fB, w);
  endif
endfunction