[glibmm] glib/glibmm/ustring.h: Fix Visual Studio macro check

[Chun-wei Fan <fanchunwei src gnome org>]

commit b078cdb597ebe9d1d52ab0a5a25397d25da91967
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Jun 15 18:24:38 2020 +0800

    glib/glibmm/ustring.h: Fix Visual Studio macro check
    
    Commit 8b8af81f accidentally changed the macro check from '_MSC_VER' to
    'MSC_VER', fix that.  It probably does not matter since Visual Studio 2017
    is required, where 'GLIBMM_HAVE_ALLOWS_STATIC_INLINE_NPOS' is enabled,
    but fix that for consistency's sake.

 glib/glibmm/ustring.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/glib/glibmm/ustring.h b/glib/glibmm/ustring.h
index dad8d549..15a63e61 100644
--- a/glib/glibmm/ustring.h
+++ b/glib/glibmm/ustring.h
@@ -30,7 +30,7 @@
 #include <type_traits>
 
 /* work around linker error on Visual Studio if we don't have GLIBMM_HAVE_ALLOWS_STATIC_INLINE_NPOS */
-#if defined(MSC_VER) && MSC_VER >= 1600 && !defined(GLIBMM_HAVE_ALLOWS_STATIC_INLINE_NPOS)
+#if defined(_MSC_VER) && _MSC_VER >= 1600 && !defined(GLIBMM_HAVE_ALLOWS_STATIC_INLINE_NPOS)
 const std::basic_string<char>::size_type std::basic_string<char>::npos = 
(std::basic_string<char>::size_type) -1;
 #endif