[glib] Makefile.msvcproj: Document things a bit better

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

commit 7d26e9ef939d8d20f7003bd2c08f705a75d1e82a
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Jan 9 12:03:06 2017 +0800

    Makefile.msvcproj: Document things a bit better
    
    If Visual Studio 2013 or later is required, let people know how this
    autotools module should be used.

 build/Makefile.msvcproj |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/build/Makefile.msvcproj b/build/Makefile.msvcproj
index a7bae54..80b818b 100644
--- a/build/Makefile.msvcproj
+++ b/build/Makefile.msvcproj
@@ -24,7 +24,11 @@
 #   dist-hook: \ # (or add to it if it is already there, note the vs9 items will also call the vs10 items in 
the process)
 #      $(top_builddir)/build/win32/vs9/YourProject.vcproj      \
 #      $(top_builddir)/build/win32/vs9/YourProject.headers
-
+#
+#   --or, if Visual Studio 2013 or later is required--
+#   dist-hook: \ # (or add to it if it is already there, this does -not- call other vs items in the process)
+#      $(top_builddir)/build/win32/vs12/gdk-4.vcxproj  \
+#      $(top_builddir)/build/win32/vs12/gdk-4.vs12.headers     \
 
 # Private functions