[gtk+/gtk-2-24] Fix introspection builds on Visual Studio 2017

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

commit 5ce6f249d74c69328d9732a4e96c1caf3e5fd4fc
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Dec 6 20:44:19 2017 +0800

    Fix introspection builds on Visual Studio 2017
    
    Detect Visual Studio 2017 properly, so that we won't mistaken it for
    2015.

 build/win32/detectenv-msvc.mak |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/build/win32/detectenv-msvc.mak b/build/win32/detectenv-msvc.mak
index 61f979d..6fd96cc 100644
--- a/build/win32/detectenv-msvc.mak
+++ b/build/win32/detectenv-msvc.mak
@@ -40,8 +40,10 @@ VSVER = 10
 VSVER = 11
 !elseif $(VCVERSION) > 1799 && $(VCVERSION) < 1900
 VSVER = 12
-!elseif $(VCVERSION) > 1899 && $(VCVERSION) < 2000
+!elseif $(VCVERSION) > 1899 && $(VCVERSION) < 1910
 VSVER = 14
+!elseif $(VCVERSION) > 1909 && $(VCVERSION) < 2000
+VSVER = 15
 !else
 VSVER = 0
 !endif