[CMake] Function for visibility definitions

[Hendrik Sattler]

Zitat von Bill Hoffman <bill.hoffman at kitware.com>:
> That said, you could have CMake configure a .h file that had this stuff
> in it.  It might be nice if the function did that automatically, as it
> is almost the same code for every project.  Then once your project was
> built with CMake, you would install the configured .h files and other
> build systems could still use the software.

OTOH, cmake is a build system, not a code generator.
This export stuff is so simple[1], why all the hassle to generate it?

HS

[1]: you only have too cases: Windows and gcc>=4. All compilers on  
Windows use the same syntax.