Because I want to make more symbols private, but that runs into a
problem with the special symbol "typeinfo for Foo" which is required for
dynamic_cast.
For clang, we can use SAL_DLLPUBLIC_RTTI to make just that magic
"typeinfo for Foo" symbol visible.
But for gcc, we are left with no option but to make the whole class
visible via <MODULE>_DLLPUBLIC.
(I have a feature request logged against gcc to support something like
that at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113958)
But I also don't want to use <MODULE>_DLLPUBLIC, since that blocks
progress of reducing symbol visibility for platforms other than gcc.
So map SAL_DLLPUBLIC_RTTI to visiblity:default for gcc, which means that
only gcc suffers the negative affects of not having that annotation.
However, that runs into the problem that gcc does not like
visibility:default in a couple of places, so I have to introduce some
extra preprocessor stuff.
Change-Id: Ib4fc5c1d2a1f8cf87d5159a4b5684137ec061605
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/164356
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
e8b9bcf021