-set( MANDIR ${CMAKE_INSTALL_PREFIX}/share/man)
-set( DATADIR ${CMAKE_INSTALL_PREFIX}/share)
-set( SYSCONFDIR /etc)
-set( DOCDIR ${CMAKE_INSTALL_PREFIX}/share/doc/tint2)
+set( MANDIR share/man CACHE PATH "Directory for man pages" )
+set( DATADIR share CACHE PATH "Directory for shared data" )
+set( SYSCONFDIR /etc CACHE PATH "Directory for configuration files" )
+set( DOCDIR share/doc/tint2 CACHE PATH "Directory for documentation files" )