diff -up src/module_list.py.orig src/module_list.py --- src/module_list.py.orig 2014-08-12 14:23:31.642985666 -0300 +++ src/module_list.py 2014-08-12 14:23:39.051985950 -0300 @@ -2107,7 +2107,7 @@ ext_modules = [ def is_package_installed(name): return False -if is_package_installed('fes'): +if 1: ext_modules.extend([ Extension("sage.libs.fes", ["sage/libs/fes.pyx"],