The only real option you have here is to manually do the conversion (or use the Makefile Project Wizard). You say you have 'a few' makefiles, don't know how much that is, but unless you're talking about > 10 or so it's not that much work to manually create a Visual Studio project for these. After all, all you do is create a new dll project and add source files to it. The default compiler/linker flags hardly need any tweaking. Oh yeah if you do tweak them, make sure to do those changes in a property sheet instead of in the project itself: the property sheet can be reused by other projects, it's a simple matter of the DRY principle.
Why is this the only real option? Firstly there is no tool that can reliably convert any arbitrary makefile to a VS project, simpy because makefiles can be in any format you want and a lot of their functionality simply has no counterpart in a VS project. Secondly, VS6 is at this date about 15 years old so even if you get it to run on your machine, the output it produces is still ancient and definitely not what you want to use for your projects.
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