library(X) compile the sources accumulated so far and build a library, X, from the resulting compiled object files. The visibility of the library is hidden.
Library(X) The same as library.
program(X) constructs an executable program named X from the given sources.
Program(X) like program, but X is exported to /bin.
build_standalone() ensures that the program being built does not depend on dynamic linking and shared libraries. To have an effect, this procedure must be called before program or Program is called.