There are lots of feature test macros like _POSIX_SOURCE,
_BSD_SOURCE, etc. chaotically placed at the beginning of
multiple files without apparent reason, sometime purely
erroneously.
This commit removes them all for the sake of cleaner code.
No new warnings are added due to that at least for gcc 5.4
on Linux with glibc 2.23.
Currently, interface-management code in the ipmitool does not allow safe
interface re-opening (i.e. closing and opening again). It is because the session
is allocated in the interface setup callback while is freed in the close
callback. So, normal re-opening of the interface, which can be required for
example durng the HPM.1 upgrade, leads to segmentation fault. That's why in the
ipmi_hpmfwupg.c instead of normal closing interface, directly access the
interface data for subsequent re-opening.
Commit for Dmitry Bazhenov
