[cairo] cairomm: Visual Studio WIN32 define clash with Surface::Type::WIN32

[James K. Lowden]

On Wed, 6 Jan 2021 18:14:08 +0100
Petr Kobalí?ek <kobalicek.petr at gmail.com> wrote:

> The problem can be fixed by introducing a synonym to WIN32 (name
> already proposed) together with still providing the old WIN32 name
> guarded by push_macro() / pop_macro() - that way no project would
> break and new projects can start using the new symbol instead.

I like your suggestion because it preserves already working code.

Myself, I'm more willing to require new users -- Windows users in
particular -- to learn about standards and to avoid undocumented
nonstandard conventions.  But your idea of an alias preserves working
code and allows for a transition in the indefinite future.  

I have two modifications to your suggestion.  

You suggest

	Surface::Type::WIN32GDI

but IIRC "GDI" is a term of art in Windows.  Unless that was your
intention, I suggest

	Surface::Type::WIN32SURFACE

instead. 

The push/pop pragmas won't work outside Visual Studio, and there are
several ways to compile for Windows without using Microsoft's
compiler.  

I think this is equivalent and portable: 

	#ifdef WIN32
	#define WIN32_WAS_SET  WIN32
	#undef WIN32
	#endif
	....
	#ifdef WIN32_WAS_SET
	#define WIN32  WIN32_WAS_SET
	#undef WIN32_WAS_SET
	#endif

--jkl