extensions: Add macro _DEFAULT_SOURCE.

Define _DEFAULT_SOURCE as _BSD_SOURCE is deprecated.
https://sourceware.org/glibc/wiki/Release/2.20#Packaging_Changes

This patch fixes the following warning:

warning: #warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use
_DEFAULT_SOURCE" [-Wcpp]
 # warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use
 # _DEFAULT_SOURCE"

Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2 files changed