Yes, there probably are not multiple threads here. It's a matter of principle to
not use smelly functions.
Also, copy the "errno" value we want to print, before calling various functions.
All our sources should include one of the "nm-default*.h" headers
first. That one drags in <config.h>, which must be included first
and a few other basics.
Which is the right "nm-default*.h" header depends on the component. In
case of "nm-daemon-helper.c", it's "libnm-std-aux/nm-default-std.h".
NSS is not available in musl libc:
./src/nm-daemon-helper/nm-daemon-helper.c:9:10: fatal error: nss.h: No such file or directory
9 | #include <nss.h>
| ^~~~~~~
(cherry picked from commit 9b802ff7f2)
Implement a new operation to resolve the hostname from an
address. Note the call to __nss_configure_lookup("hosts", "dns"): this
configures the glibc Name Service Switch (NSS) to only use DNS,
bypassing other modules that might be configured in
/etc/nsswitch.conf. Other modules like 'myhostname' or 'resolve' can
return synthesized names, while we are only interested in real DNS
results.
(cherry picked from commit 648b0848f1)
