uClibc doesn't implement strerror_l() and thus libnl starting from
3.2.29 couldn't be compiled with it any longer, see
6c2d111177
To work-around that problem we'll just do a check on strerror_l()
availability during configuration and if it's not there just fall back
to locale-less strerror().
Patch for libnl is alreadfy merged upstream, see
e15966ac7f
and once the next libnl release happens this one must be removed from
Lede/OpenWrt.
Signed-off-by: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: John Crispin <john@phrozen.org>
Cc: Daniel Engberg <daniel.engberg.lists@pyret.net>