Since
8162464a25e we do so in win32_port.h. But it likely didn't do much
before that either, because at that point windows.h was already included via
win32_port.h.
Reported-By: Tom Lane
Discussion: https://postgr.es/m/612842.
1636237461@sss.pgh.pa.us
#include "postgres.h"
-#define WIN32_LEAN_AND_MEAN
-
/*
* Some versions of the MS SDK contain "typedef enum { ... } ;" which the MS
* compiler quite sanely complains about. Well done, Microsoft.