is_selinux_enabled() in original libselinux returns 1 if selinux was 
enabled and 0 is selinux was disabled or checking if it's 
enabled/disabled failed. For example if we don't have /proc mounted 
then original is_selinux_enabled() will return 0.

In fedora erros checking has been added and now if we don't have proc 
is_selinux_enabled() returns -1 which causes serious problems with 
almost every selinux enabled apps in fedora because current 
is_selinux_enabled is:

if (is_selinux_enabled()) {
  do something
}

so in case of error (-1) that part of code will be executed (even if 
in reality we do not have selinux support in our custom kernel).

I should rather submit this for each selinux package which uses 
is_selinux_enabled in way described above but...