FL_ABI_VERSION should not be set in the IDE projects to avoid having to
update the version numbers for each release.
The default is used if FL_ABI_VERSION is not defined.
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10788 ea41ed52-d2ee-0310-a9c1-e6b18d33e121