stackloop: `main` should return `int`, not `void`

[Samuel Gruetter]

bedrock2 currently fails to build on my system because bedrock2/special/stackloop returns a random garbage non-zero exit code:

[sam@samsdell special]$ ./stackloop 
[sam@samsdell special]$ echo $?
159
[sam@samsdell special]$ ./stackloop 
[sam@samsdell special]$ echo $?
239
[sam@samsdell special]$ ./stackloop 
[sam@samsdell special]$ echo $?
143
[sam@samsdell special]$ ./stackloop 
[sam@samsdell special]$ echo $?
159

According to a quick google search, a C main function's return type must be int, and void is not allowed (however, omitting the return statement in main is allowed, and it will default to 0 in that case).

My first idea to fix it was to change the bedrock2 source to have one return value, but then the pretty-printer would print uintptr_t as the return type instead of int. Another way would be to manually write a main function in the .v file like in ToCStringExprTypecheckingTest.v. For the moment, I just replaced special/stackloop by special/stackloop ; true locally in my Makefile, but can you please apply a proper fix @andres-erbsen ?

[Jason Gross]

the pretty-printer would print uintptr_t as the return type instead of int

Is this actually an issue? If gcc accepts a void main function, it wouldn't surprise me if it also accepted other sorts of return types and just did a cast.