I don't have a bundle for Makefiles in my version of Textmate (1.5.8). Makefiles are treated as plain text files.
I haven't found one listed via the GetBundles bundle. (I installed CMake, but that doesn't appear to be it.) I've also looked through the bundle listhttp://svn.textmate.org/trunk/Bundles/and don't see one.
Where is the Makefile bundle.