patch 8.2.1381: MS-Windows: crash with Python 3.5 when stdin is redirected

Problem:    MS-Windows: crash with Python 3.5 when stdin is redirected.
Solution:   Reconnect stdin. (Yasuhiro Matsumoto, Ken Takata, closes #6641)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index dedc98d..1c519d9 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -588,6 +588,8 @@
 CFLAGS += -DFEAT_PYTHON3
  ifeq (yes, $(DYNAMIC_PYTHON3))
 CFLAGS += -DDYNAMIC_PYTHON3 -DDYNAMIC_PYTHON3_DLL=\"$(DYNAMIC_PYTHON3_DLL)\"
+ else
+CFLAGS += -DPYTHON3_DLL=\"$(DYNAMIC_PYTHON3_DLL)\"
  endif
 endif