cmake: Don't export symbols if building static library

[orudge]

If you build tinyxml2 as a static library on Windows, its symbols are exported from any DLL or EXE you create. This generally shouldn't happen.

[traversaro]

Instead of having a COMPILE_DEFINITIONS target depends on BUILD_SHARED_LIBS, could it make sense to set directly the DEFINE_SYMBOL of the tinyxml2 target to TINYXML2_EXPORT, as, despite its name DEFINE_SYMBOL specifies a define that is only used when the library is used as shared?

[orudge]

Instead of having a COMPILE_DEFINITIONS target depends on BUILD_SHARED_LIBS, could it make sense to set directly the DEFINE_SYMBOL of the tinyxml2 target to TINYXML2_EXPORT, as, despite its name DEFINE_SYMBOL specifies a define that is only used when the library is used as shared?

That looks like a better fix, thanks!

[orudge]

I've just seen that #805 also fixes this issue, though I think the change that @traversaro suggested makes this a better fix. It would be good if we could get this change included in the next release though if possible.

[leethomason]

Please see #804. There are so many build PRs open I'm not sure the best approach to reconcile them.