getaddrinfo: fix sh typo in gai_strerrorA decl checking

getaddrinfo: fix sh typo in gai_strerrorA decl checking

* m4/getaddrinfo.m4 (gl_GETADDRINFO): Fix typo in the generated
shell code: it contained a 'break' that was not in a loop.
Apparently the macro assumed that AC_CHECK_DECLS is implemenented
via a shell-language loop; this may have been true in old Autoconf
versions, but it's not true in Autoconf 2.68.  I found this bug
when testing coreutils git on Solaris 8, whose shell complains
about the syntax error.