generated main should be int not void

[erikkaplun]

Consider http://lpaste.net/470595860065943552:

Currently, the main function generated by writeC has void as it's return type, leading to:

main.c:90:1: error: 'main' must return 'int'
void main()
^~~~
int
1 error generated.

[ggreif]

I guess this is fixed now:

atom/Language/Atom/Example/External.hs

Line 44 in bc7ab55

, unlines [ "int main(void) {"

Well, scratch that... atom won't emit a main() function, is is usually written by the user of the DSL. Like in the above example.