It may not be perfect for your scenario, but SlickEdit does support opening a workspace from a Makefile.
Project > Open Other Workspace > Makefile...
It will scan your Makefile for build targets and also try to deduce the list of source files. Since Makefiles are built in a lot of different ways, and certain make implementations have non-standard extensions, this feature can be kind of hit or miss, but you certainly can give it a test drive. Performance can be a bit hit or miss with this feature, because SlickEdit will rescan the makefile every time the workspace is opened to determine if new files have been added to the project.
The other option is to create a generic C/C++ project and specify that it is to be built using a Makefile in Project Properties.
Neither of these solutions will give you integrated debugging straight out of the box, because we can't predict in what magical corner of the universe the Makefile will place the executable. So you may have to make a couple more mods in Project Properties to get that going.