Everyplace else thinks it's _WIN64, so make these places fall in line.
The pg_regress.c usage is not going to result in any change in behavior,
only suppressing (or not) a compiler warning about downcasting HANDLEs.
So there seems no need for back-patching there.
The libpq/win32.mak usage might represent an actual bug, if anyone were
using this script to build for Windows64, which perhaps nobody is.
Given the lack of field complaints, no back-patch here either.
pg_regress.c problem found by Christian Ullrich, the other by me.
!MESSAGE Building the Win32 static library...
!MESSAGE
!ELSEIF ("$(CPU)" == "IA64")||("$(CPU)" == "AMD64")
-ADD_DEFINES=/D "WIN64" /Wp64 /GS
+ADD_DEFINES=/D "_WIN64" /Wp64 /GS
ADD_SECLIB=bufferoverflowU.lib
!MESSAGE Building the Win64 static library...
!MESSAGE
postmaster_running = true;
-#ifdef WIN64
+#ifdef _WIN64
/* need a series of two casts to convert HANDLE without compiler warning */
#define ULONGPID(x) (unsigned long) (unsigned long long) (x)
#else