INSTALL: mention not to install msinttypes package in OSGeo4W

INSTALL

@@ -442,6 +442,11 @@ and from OSGeo4W (select Advanced Installation):
 
 This will also select packages the above packages depend on.
 
+If you install other packages, this might cause issues. Particularly, make sure
+*not* to install the msinttypes package. It installs a stdint.h file
+in OsGeo4W[64]\include, that conflicts with Visual Studio own stdint.h, which
+for example breaks the build of the virtuallayer provider.
+
 Earlier versions of this document also covered how to build all above
 dependencies.  If you're interested in that, check the history of this page in the Wiki
 or the SVN repository.