Comment from Marco [here](https://github.com/bitcoin/bitcoin/pull/19954#discussion_r503075378):
> + make -C src --jobs=1 check-security V=1
make: Entering directory '/bitcoin/distsrc-x86_64-linux-gnu/src'
Checking binary security...
READELF=/gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/x86_64-linux-gnu-readelf OBJDUMP=x86_64-linux-gnu-objdump OTOOL= /gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/python3.7 ../contrib/devtools/security-check.py bitcoind  bitcoin-cli bitcoin-tx bitcoin-wallet test/test_bitcoin bench/bench_bitcoin qt/bitcoin-qt  
make: Leaving directory '/bitcoin/distsrc-x86_64-linux-gnu/src'
> + case "$HOST" in
> + make -C src --jobs=1 check-symbols V=1
make: Entering directory '/bitcoin/distsrc-x86_64-linux-gnu/src'
Checking glibc back compat...
READELF=/gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/x86_64-linux-gnu-readelf CPPFILT=/gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/x86_64-linux-gnu-c++filt /gnu/store/pzq9s5ldl90h72p26jkdakyccdg9ib3k-profile/bin/python3.7 ../contrib/devtools/symbol-check.py bitcoind  bitcoin-cli bitcoin-tx bitcoin-wallet test/test_bitcoin bench/bench_bitcoin qt/bitcoin-qt  
test/test_bitcoin: export of symbol in6addr_loopback not allowed
test/test_bitcoin: failed EXPORTED_SYMBOLS
make: *** [Makefile:20952: check-symbols] Error 1
make: Leaving directory '/bitcoin/distsrc-x86_64-linux-gnu/src'

**test/test_bitcoin: export of symbol in6addr_loopback not allowed**
{
    CNetAddr addr1(ResolveIP("1.2.3.4"));
    CNetAddr addr2(ResolveIP("::FFFF:0102:0304"));
    BOOST_CHECK(addr2.IsIPv4());
    BOOST_CHECK_EQUAL(addr1.ToString(), addr2.ToString());
}
BOOST_AUTO_TEST_CASE(subnet_test)
{
    BOOST_CHECK(ResolveSubNet("1.2.3.0/24") == ResolveSubNet("1.2.3.0/255.255.255.0"));
    BOOST_CHECK(ResolveSubNet("1.2.3.0/24") != ResolveSubNet("1.2.4.0/255.255.255.0"));
    BOOST_CHECK(ResolveSubNet("1.2.3.0/24").Match(ResolveIP("1.2.3.4")));
    BOOST_CHECK(!ResolveSubNet("1.2.2.0/24").Match(ResolveIP("1.2.3.4")));
    BOOST_CHECK(ResolveSubNet("1.2.3.4").Match(ResolveIP("1.2.3.4")));
    BOOST_CHECK(ResolveSubNet("1.2.3.4/32").Match(ResolveIP("1.2.3.4")));
    BOOST_CHECK(!ResolveSubNet("1.2.3.4").Match(ResolveIP("5.6.7.8")));
    BOOST_CHECK(!ResolveSubNet("1.2.3.4/32").Match(ResolveIP("5.6.7.8")));
    BOOST_CHECK(ResolveSubNet("::ffff:127.0.0.1").Match(ResolveIP("127.0.0.1")));
    BOOST_CHECK(ResolveSubNet("1:2:3:4:5:6:7:8").Match(ResolveIP("1:2:3:4:5:6:7:8")));
    BOOST_CHECK(!ResolveSubNet("1:2:3:4:5:6:7:8").Match(ResolveIP("1:2:3:4:5:6:7:9")));
    BOOST_CHECK(ResolveSubNet("1:2:3:4:5:6:7:0/112").Match(ResolveIP("1:2:3:4:5:6:7:1234")));
    BOOST_CHECK(ResolveSubNet("192.168.0.1/24").Match(ResolveIP("192.168.0.2")));
    BOOST_CHECK(ResolveSubNet("192.168.0.20/29").Match(ResolveIP("192.168.0.18")));
    BOOST_CHECK(ResolveSubNet("1.2.2.1/24").Match(ResolveIP("1.2.2.4")));
    BOOST_CHECK(ResolveSubNet("1.2.2.110/31").Match(ResolveIP("1.2.2.111")));
    BOOST_CHECK(ResolveSubNet("1.2.2.20/26").Match(ResolveIP("1.2.2.63")));
    
    BOOST_CHECK(ResolveSubNet("::/0").Match(ResolveIP("1:2:3:4:5:6:7:1234")));