Function-like macro semicolon inconsistency fix

[Ricardicus]

I was using pybind11 to wrap a class containing virtual and pure virtual functions.

I noticed that the function-like macros: PYBIND11_OVERLOAD and PYBIND11_OVERLOAD_PURE behaved a bit differently when I was compiling my program.

I ran into errors where the compiler complained that I was missing a semicolon when using PYBIND11_OVERLOAD but it did not complain when I was using PYBIND11_OVERLOAD_PURE.
So there is an inconsistency here making PYBIND11_OVERLOAD_PURE statements ok without semicolons.

What I am trying to say in code:

/* Compiler thinks this is fine */
PYBIND11_OVERLOAD_PURE( .... )
PYBIND11_OVERLOAD_PURE( .... )

/* Compiler does not think this is fine */
PYBIND11_OVERLOAD( .... )
PYBIND11_OVERLOAD( .... )

/* I must add semicolons to make it happy */
PYBIND11_OVERLOAD( .... );
PYBIND11_OVERLOAD( .... );

There is a slight inconsistency here.

I introduced a change so that PYBIND11_OVERLOAD can be called with or without semicolons and I thought perhaps maybe you would like to see it also.

[Ricardicus]

One can go two directions here; either force the semicolon to be added or let it be optional.

However since the _PURE macro has no need for a semicolon to end it, I went with making the other optional just for backward compatibilty, maybe there are projects out there with PYBIND11_OVERLOAD_PURE statements without semicolon...

[Ricardicus]

I see you have fixed this now 👍

[YannickJadoul]

Thanks for the PR, though, @Ricardicus! It was decided to fix the naming and make the semicolons mandatory, while we're at it :-)