doxygen: exclude EXPORT_SYMBOL and skip .git files
doxygen: exclude EXPORT_SYMBOL and skip .git files

Signed-off-by: Pablo Neira Ayuso <707d14912bb250caf67dfe0ea4035681fbfc4f56@netfilter.org>

fqrouter/libmnl,vyos/libmnl,chamaken/libmnl,remfalc/vyt-libmnl,greearb/libmnl-ct,Distrotech/libmnl,vyatta/libmnl,cyclops8456/libmnl,threatstack/libmnl,cyclops8456/libmnl,vyos/libmnl,cyclops8456/libmnl,vyos/libmnl,chamaken/libmnl,vyatta/libmnl,fqrouter/libmnl,remfalc/vyt-libmnl,Distrotech/libmnl,threatstack/libmnl,greearb/libmnl-ct