patch 8.0.1741: MS-Windows with msys2 cannot build Ruby statically

Problem:    MS-Windows with msys2 cannot build Ruby statically.
Solution:   Add RUBY_VERSION to CFLAGS later. (Gray Wolf, closes #2833)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index b21a1d4..d51b6ea 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -458,7 +458,6 @@
 endif
 ifeq (no, $(DYNAMIC_RUBY))
 RUBYLIB = -L$(RUBY)/lib -l$(RUBY_INSTALL_NAME)
-CFLAGS += -DRUBY_VERSION=$(RUBY_VER)
 endif
 
 endif # RUBY
@@ -538,6 +537,9 @@
 CFLAGS += -DDYNAMIC_RUBY -DDYNAMIC_RUBY_DLL=\"$(RUBY_INSTALL_NAME).dll\"
 CFLAGS += -DDYNAMIC_RUBY_VER=$(RUBY_VER)
 endif
+ifeq (no, $(DYNAMIC_RUBY))
+CFLAGS += -DRUBY_VERSION=$(RUBY_VER)
+endif
 ifneq ($(findstring w64-mingw32,$(CC)),)
 # A workaround for MinGW-w64
 CFLAGS += -DHAVE_STRUCT_TIMESPEC -DHAVE_STRUCT_TIMEZONE