getaddrinfo: Fix calling convention in 32-bit mode on native Windows. * m4/getaddrinfo.m4 (gl_GETADDRINFO): Test whether getaddrinfo has a non-POSIX signature. If so, set REPLACE_GETADDRINFO. Define HAVE_GETADDRINFO as a C macro. * lib/netdb.in.h (getaddrinfo, freeaddrinfo): If REPLACE_GETADDRINFO, declare as replacement functions. * lib/getaddrinfo.c (getaddrinfo, freeaddrinfo): If HAVE_GETADDRINFO, define as no-op overrides. * m4/netdb_h.m4 (gl_NETDB_H_DEFAULTS): Initialize REPLACE_GETADDRINFO. * modules/netdb (Makefile.am): Substitute REPLACE_GETADDRINFO. * modules/getaddrinfo (Depends-on, configure.ac): Test REPLACE_GETADDRINFO. * doc/posix-functions/getaddrinfo.texi: Mention calling convention problem. * doc/posix-functions/freeaddrinfo.texi: Mention header file and calling convention problems.