Consider the following program tmp.py:

import sys, getopt
print(getopt.getopt(sys.argv[1:], '', ['help']))

The program accept "--help" without a value:

python helloworld.py --help

But if someone invoke the program like:

python helloworld.py --help=

Python should raise an error.

"--help=" is not considered as no_argument in libc's getopt implementation (tested on Mac OS X 
Leopard):

#include <getopt.h>

static struct option longopts[] = { 
        { "help", no_argument, NULL, "h" },
};

#include <getopt.h>

static struct option longopts[] = { 
        { "help", no_argument, NULL, 'h' },
};

int main(int argc, char **argv)
{
        while (getopt_long(argc, argv, "h", longopts, NULL) != -1);
        return 0;
}

macbook:~/tmp$ gcc -o tmp tmp.c
macbook:~/tmp$ ./tmp --help=
tmp: option `--help' doesn't allow an argument
macbook:~/tmp$

Can you please also write a regression test in 
Lib/test/test_getopt.py?

Updated patch with a regression test.

The patch is good.