Apply Canna-3.7p3-redecl.patch from fedora project.
http://pkgs.fedoraproject.org/cgit/Canna.git/tree/Canna-3.7p3-redecl.patch
Apply Canna-3.7p3-fix-gcc4-warning.patch from fedora project.
http://pkgs.fedoraproject.org/cgit/Canna.git/tree/Canna-3.7p3-fix-gcc4-warning.patch