Oh. Sounds like a short explanation of what a compiler is might clear this up a bit.
A compiler is not an Integrated Development Environment (I'm assuming that you think it is, since they tend to be closely linked on Windows), it just compiles source code to a binary format so it can then get linked into a usable binary executable by the linker. This is pretty much always software with exclusively a command line interface that the user seldom calls directly.
The point of adding them was to go "here's two compilers for software developers coming over, they're fully compliant and come with libraries that support everything up to the newest standard". Most people won't use these from the command line, but instead from an IDE (such as KDevelop, Geany or Eclipse or what have you).
At this point the LLVM acronym means absolutely nothing since LLVM is just a widely-used compiler infrastructure. No emulation is done and nothing special is required to run binaries compiled using Clang, it's just a widely used alternative to GCC that some people prefer.
I'm not sure if I'd call vim or emacs simple. If you're going for that, you should probably replace both of them in the list with just GNU nano and Kate.
*make is a tool for automatically compiling a software project. It processes a makefile with instructions and then builds your project for you according to those instructions. It calls compiler, linker, etc. Can be thought of like a shellscript with the express purpose of compiling applications and/or libraries.