A program that runs forever and does nothing.

It also doesn't take a lot of resources while doing so.

Simply use make with the provided Makefile

make

The source contains debian/ subdirectory with the meta files required to create a Debian package with debuild.

The program uses a call to select() without file descriptors to sleep indefinitely without taking much ressurces.

select() without file descriptor does this, see for example the following excerpt from the Linux man page for select():

Some code calls select() with all three sets empty, nfds zero, and a non-NULL timeout as a fairly portable way to sleep with subsecond precision.