mapi/glapi: Fix dll linkage of GLES1 symbols.
This fixes several MSVC warnings like: warning C4273: 'glClearColorx' : inconsistent dll linkage In fact, we should avoid using `declspec(dllexport)` altogether, and use exclusively the .DEF instead, which gives more precise control of which symbols must be exported, but all the public GL/GLES headers practically force us to pick between `declspec(dllexport)` or `declspec(dllimport)`. Cc: "10.4" <mesa-stable@lists.freedesktop.org> Reviewed-by:Brian Paul <brianp@vmware.com> Reviewed-by:
Roland Scheidegger <sroland@vmware.com> (cherry picked from commit 5fdb6d68)