* include/freetype/internal/ftcalc.h (FT_MSB): Use `_MSC_VER' value.

Older VC versions don't provide `_BitScanReverse'.  We test for VC
2013.

Reported by John Emmas <john@creativepost.co.uk>.

ChangeLog

@@ -1,3 +1,12 @@
+2018-05-18  Werner Lemberg  <wl@gnu.org>
+
+	* include/freetype/internal/ftcalc.h (FT_MSB): Use `_MSC_VER' value.
+
+	Older VC versions don't provide `_BitScanReverse'.  We test for VC
+	2013.
+
+	Reported by John Emmas <john@creativepost.co.uk>.
+
 2018-05-17  Werner Lemberg  <wl@gnu.org>
 
 	s/inline/__inline/ for MSVC.

include/freetype/internal/ftcalc.h

@@ -353,10 +353,10 @@ FT_BEGIN_HEADER
 
 #define FT_MSB( x )  ( 31 - __builtin_clzl( x ) )
 
-#endif
+#endif /* __GNUC__ */
 
 
-#elif defined( _MSC_VER )
+#elif defined( _MSC_VER ) && ( _MSC_VER >= 1800 )
 
 #if FT_SIZEOF_INT == 4
 
@@ -368,6 +368,7 @@ FT_BEGIN_HEADER
     unsigned long  where;
 
 
+    /* not available in older VC versions */
     _BitScanReverse( &where, x );
 
     return (FT_Int32)where;
@@ -377,7 +378,8 @@ FT_BEGIN_HEADER
 
 #endif
 
-#endif
+#endif /* _MSC_VER */
+
 
 #endif /* !FT_CONFIG_OPTION_NO_ASSEMBLER */