diff -up src/module_list.py.orig src/module_list.py --- src/module_list.py.orig 2014-08-12 14:02:16.914936853 -0300 +++ src/module_list.py 2014-08-12 14:02:26.626937225 -0300 @@ -2103,7 +2103,8 @@ ext_modules = [ # These extensions are to be compiled only if the # corresponding packages have been installed -from sage.misc.package import is_package_installed +def is_package_installed(name): + return False if is_package_installed('fes'): ext_modules.extend([