[librsvg/librsvg-2.40] build: Fix Visual Studio 2017 introspection builds

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

commit 1f3101b0509d76583a940f4662d964cb199ea0c8
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Oct 4 23:51:25 2017 +0800

    build: Fix Visual Studio 2017 introspection builds
    
    We need to be able to detect Visual Studio 2017 properly in the NMake
    Makefiles.

 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