Ensure that only the files a copied and not the directory
itself.
install(DIRECTORY demos DESTINATION ${CMAKE_INSTALL_DATAROOTDIR})
-install(DIRECTORY doc DESTINATION ${CMAKE_INSTALL_DOCDIR})
-+install(FILES doc/vym.pdf doc/vym_fr.pdf doc/vym_es.pdf DESTINATION ${CMAKE_INSTALL_DOCDIR})
++install(DIRECTORY doc/ DESTINATION ${CMAKE_INSTALL_DOCDIR} FILES_MATCHING PATTERN "*.pdf")
install(FILES doc/vym.1.gz DESTINATION ${CMAKE_INSTALL_MANDIR})
-install(FILES README.md LICENSE.txt DESTINATION ${CMAKE_INSTALL_DOCDIR})
+install(FILES README.md DESTINATION ${CMAKE_INSTALL_DOCDIR})