Makefile: WARNINGS: add -Wsync-nand
Makefile: WARNINGS: add -Wsync-nand

-Wsync-nand (C and C++ only)
  Warn when "__sync_fetch_and_nand" and "__sync_nand_and_fetch"
  built-in functions are used.  These functions changed semantics
  in GCC 4.4.

Signed-off-by: Ferry Huberts <66e11f9f5d965b69497c7e73d5e808f8b13c1218@pelagic.nl>

duydb2/olsr,servalproject/olsr,duydb2/olsr,diogomg/olsrd,diogomg/olsrd,diogomg/olsrd,sebkur/olsrd,servalproject/olsr,ninuxorg/olsrd,diogomg/olsrd-binary-heap,acinonyx/olsrd,nolith/olsrd,zioproto/olsrd,cholin/olsrd,sebkur/olsrd,ninuxorg/olsrd,servalproject/olsr,sebkur/olsrd,diogomg/olsrd-binary-heap,diogomg/olsrd-binary-heap,diogomg/olsrd-binary-heap,duydb2/olsr,ninuxorg/olsrd,acinonyx/olsrd,zioproto/olsrd,duydb2/olsr,acinonyx/olsrd,sebkur/olsrd,diogomg/olsrd-binary-heap,cholin/olsrd,tdz/olsrd,cholin/olsrd,tdz/olsrd,diogomg/olsrd,ninuxorg/olsrd,cholin/olsrd,zioproto/olsrd,duydb2/olsr,diogomg/olsrd,acinonyx/olsrd,cholin/olsrd,tdz/olsrd,ninuxorg/olsrd,nolith/olsrd,duydb2/olsr,nolith/olsrd,diogomg/olsrd-binary-heap,diogomg/olsrd-binary-heap,servalproject/olsr,duydb2/olsr,tdz/olsrd,diogomg/olsrd,servalproject/olsr,nolith/olsrd,sebkur/olsrd,diogomg/olsrd,servalproject/olsr,nolith/olsrd,acinonyx/olsrd,sebkur/olsrd,duydb2/olsr,zioproto/olsrd,zioproto/olsrd,tdz/olsrd