function pkgNameSorter( a, b ) {
	if ( startsWith( a, '@stdlib' ) ) {
		if ( startsWith( b, '@stdlib' ) ) {
			return a.localeCompare( b );
		}
		return 1;
	}
	if ( startsWith( b, '@stdlib' ) ) {
		return -1;
	}
	return a.localeCompare( b );
}
Sorting function for dependencies.

## Notes

-   External packages are placed before `@stdlib` packages
-   Package names are sorted in alphabetical order

@private
@param {string} a - first package name
@param {string} b - second package name
@returns {integer} `1` to indicate `a` should be placed before `b`, `-1` if `b` should be placed before `a`, `0` otherwise