fexecle() - executes a program
fexecle(name, in, out, err, a0, a1, a2, ... NULL, envptr)
char *name;
FILE *in, *out, *err;
char *a0, *a1, *a2...;
char **envptr;
fexecle() is a variation of fexecve(). The description for fexecve() also
applies to fexecle() except for the argument list. fexecle() permits the
argument list, which is a vector of pointers with a NULL at the end, to be
constructed as part of the call to fexecle(), rather than as a C vector. Thus,
in the new program, av[0] will be the same as a0 in this program, etc.
Returns a system error code; fexecle() does not return if it succeeds.