(ITS#8376) Use getaddrinfo to resolve FQDN

[hguo@suse.com]

Full_Name: Howard Guo
Version: 2.4.44
OS: openSUSE
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (195.135.221.2)


In a pure IPv6 environment, if LDAP is used as the host resolve, the host may
hang when it attempts to resolve its own host name due to usage of
gethostbyname*, in the following sequence of events:

nss_ldap: locks mutex
nss_ldap: calls libldapA-A-> libldap: gethostbyname
-> nss_ldap: lock mutex and hang

See patch file "howard-guo-160222.patch".