Description:

The makedepend program reads each sourcefile in sequence and parses it
like a C-preprocessor, processing all "#include", "#define", "#undef",
"#ifdef", "#ifndef", "#endif", "#if", "#elif" and "#else" directives
so that it can correctly tell which #include directives would be used
in a compilation. Any "#include", directives can reference files
having other "#include" directives, and parsing will occur in these
files as well.

Every file that a sourcefile includes, directly or indirectly, is what
makedepend calls a dependency. These dependencies are then written to
a makefile in such a way that make will know which object files
must be recompiled when a dependency has changed.