My question may be silly, but I need to use a library from its source code without compiling it to a library form first. The tool in question is FreeType. Is this possible?
You can add all the files from the FreeType source distribution into your own project, and try to get them to compile alongside. However, the FreeType compilation procedure is a bit tricky, if I recall correctly.
It is probably easier to compile FreeType as a static library, then link your own program with the generated library. If you do that, your executable will have no dependency on the FreeType runtime library.