Consistenly use #ifdef to check for AC_DEFINE'd macros

* aio.c (print_common_flags): Use #ifdef in the check for
HAVE_STRUCT_IOCB_U_C_FLAGS.
* defs.h: Use #ifdef in the check for HAVE_LITTLE_ENDIAN_LONG_LONG.
* net.c: Use #ifdef in the check for HAVE_SENDMSG.
* syscall.c (dumpio): Likewise.
* printstat.h (DO_PRINTSTAT): Use #ifdef in checks for
HAVE_STRUCT_STAT_ST_* macros.
* util.c: Use #ifdef in checks for HAVE_SYS_XATTR_H.
6 files changed