build: fix _BSD_SOURCE complier warning
When compiling xfstests with either gcc 6.4.1 or 7.2.1 I see the
following warning:
In file included from /usr/include/stdio.h:27:0,
from fssum.c:25:
/usr/include/features.h:148:3: warning: #warning "_BSD_SOURCE and _SVID_SOURCE
are deprecated, use _DEFAULT_SOURCE" [-Wcpp]
# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
^~~~~~~
The feature_test_macros(7) man page says this about _BSD_SOURCE:
Since glibc 2.20, this macro is deprecated. It now has the same
effect as defining _DEFAULT_SOURCE, but generates a compile-time
warning (unless _DEFAULT_SOURCE is also defined). Use
_DEFAULT_SOURCE instead. To allow code that requires _BSD_SOURCE
in glibc 2.19 and earlier and _DEFAULT_SOURCE in glibc 2.20 and
later to compile without warnings, define both _BSD_SOURCE and
_DEFAULT_SOURCE.
Keep backwards compatibility with older code by defining both
_BSD_SOURCE and _DEFAULT_SOURCE.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>