build: fix linker issue when LDFLAGS contains --as-needed

The link of iptables-save fails on:

$ make LDFLAGS="-Wl,--as-needed"
[...]
extensions/libext4.a(libxt_RATEEST.o): In function `RATEEST_final_check':
extensions/libxt_RATEEST.c:164: undefined reference to `log'

Helpful Reference: http://www.gentoo.org/proj/en/qa/asneeded.xml
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
1 file changed