libsimple.h includes most POSIX header files so you do need to include lots of
headers in your code, and defines macros and functions that are useful for most
programs and libraries to simplify the code. It also provides *_MIN and *_MAX
values for integer data types.

All functions are namespaced with `libsimple_` and aliased with macro
definitions to unnamespaced names unless there already is a macro with that
name. However, some functions are seen as libsimple specific and do not
have unnamespaced.

Programs using this library should define `char *argv0` and set it to
the 0:th command line argument.