Upgrade alpine
Ref https://github.com/znc/znc-docker/issues/19
-FROM alpine:3.8
+FROM alpine:3.10
ARG VERSION_EXTRA=""
-# musl silently doesn't support AI_ADDRCONFIG yet, and ZNC doesn't support Happy Eyeballs yet.
-# Together they cause very slow connection. So for now IPv6 is disabled here.
-ARG CMAKEFLAGS="-DVERSION_EXTRA=${VERSION_EXTRA} -DCMAKE_INSTALL_PREFIX=/opt/znc -DWANT_CYRUS=YES -DWANT_PERL=YES -DWANT_PYTHON=YES -DWANT_IPV6=NO"
+ARG CMAKEFLAGS="-DVERSION_EXTRA=${VERSION_EXTRA} -DCMAKE_INSTALL_PREFIX=/opt/znc -DWANT_CYRUS=YES -DWANT_PERL=YES -DWANT_PYTHON=YES"
ARG MAKEFLAGS=""
ARG BUILD_DATE
-Subproject commit 4da25330d7d4415507c5abd24efa74130243a5b3
+Subproject commit 95e45def730df4a04c0d08a97dccb66e5b9766f6