Define WIN32_STACK_RLIMIT throughout win32 and cygwin builds.

The MSVC build system already did this, and commit
617dc6d299 used it in a second file.
Back-patch to 9.4, like that commit.

Discussion: https://postgr.es/m/CAA8=A7_1SWc3+3Z=-utQrQFOtrj_DeohRVt7diA2tZozxsyUOQ@mail.gmail.com

src/backend/tcop/Makefile

@@ -14,8 +14,4 @@ include $(top_builddir)/src/Makefile.global
 
 OBJS= dest.o fastpath.o postgres.o pquery.o utility.o
 
-ifneq (,$(filter $(PORTNAME),cygwin win32))
-override CPPFLAGS += -DWIN32_STACK_RLIMIT=$(WIN32_STACK_RLIMIT)
-endif
-
 include $(top_srcdir)/src/backend/common.mk

src/makefiles/Makefile.cygwin

@@ -14,6 +14,8 @@ AROPT = crs
 DLSUFFIX = .dll
 CFLAGS_SL =
 
+override CPPFLAGS += -DWIN32_STACK_RLIMIT=$(WIN32_STACK_RLIMIT)
+
 ifneq (,$(findstring backend,$(subdir)))
 ifeq (,$(findstring conversion_procs,$(subdir)))
 ifeq (,$(findstring libpqwalreceiver,$(subdir)))

src/makefiles/Makefile.win32

@@ -8,6 +8,8 @@ BE_DLLLIBS= -L$(top_builddir)/src/backend -lpostgres
 override CPPFLAGS+="-I$(top_srcdir)/src/include/port/win32"
 endif
 
+override CPPFLAGS += -DWIN32_STACK_RLIMIT=$(WIN32_STACK_RLIMIT)
+
 AROPT = crs
 DLSUFFIX = .dll
 CFLAGS_SL =