More #ifdef fun: src/interfaces/libpq/win32.c

src/interfaces/libpq/win32.c contains

/* Declared here to avoid pulling in all includes, which causes name collissions */ 
#ifdef ENABLE_NLS
extern char *
libpq_gettext(const char *msgid)
__attribute__((format_arg(1)));
#else
#define libpq_gettext(x) (x)
#endif

Now, since it has nowhere bothered to #include pg_config.h, ENABLE_NLS
will certainly not be defined, and so this code always fails to invoke
gettext.

This may not be real important since the file appears to use gettext
only here:
if (!success)    sprintf(strerrbuf, libpq_gettext("Unknown socket error (0x%08X/%i)"), err, err);

but it's still pretty bogus.

Without a Windows machine, I'm not in a position to try making this file
properly include postgres_fe.h, or at least c.h, but someone ought to
try harder.
        regards, tom lane