Partially fix obsolete comment.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/jk/trunk@1572023 13f79535-47bb-0310-9956-ffa450edef68
Be more explicit with default for prefer_ipv6.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/jk/trunk@1572024 13f79535-47bb-0310-9956-ffa450edef68
An empty if-given block in AC_ARG_ENABLE
for sock-cloexec would disable SOCK_CLOEXEC
in both cases, "--disable-sock-cloexec"
and "--enable-sock-cloexec".

Support the theoretical "--enable-sock-cloexec"
case by checking enableval like we do for
other cases. Enable is now doing auto-detection,
the same as was the default (no switch given) before.


git-svn-id: https://svn.apache.org/repos/asf/tomcat/jk/trunk@1572028 13f79535-47bb-0310-9956-ffa450edef68