A makefile is built out of a set of targets which we want to build
and intermediate targets used in the build process.
In a makefile, the target is followed by a colon (:), which is then
followed by a list of its dependent targets or files (commonly referred to
as dependencies).
Afterwards in a new line, there should be a tab character (and not any other
whitespace before or afterwards), followed by the command used to generate the
target from the dependencies.