win32.h: fix macro name

* include/ruby/win32.h: fix macro name for VC runtime version,
  RT_VER is only in Makefile.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51760 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Fri Sep  4 23:26:22 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* include/ruby/win32.h: fix macro name for VC runtime version,
+	  RT_VER is only in Makefile.
+
 Fri Sep  4 17:46:17 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* doc/contributing.rdoc: fix configuration option.

include/ruby/win32.h

@@ -170,7 +170,7 @@ typedef int clockid_t;
 #define off_t __int64
 #define stat stati64
 #define fstat(fd,st)		fstati64(fd,st)
-#if !defined(_MSC_VER) || RT_VER < 80
+#if !defined(_MSC_VER) || RUBY_MSVCRT_VERSION < 80
 #define stati64 _stati64
 #ifndef _stati64
 #define _stati64(path, st) rb_w32_stati64(path, st)