This is a trivial RPN calculator. It is meant to explain ELF sections
(or named sections in general).

	when
	====

It was born as code to be written during a lesson, and the first
commit here is actually what I wrote on 2009-05-20 while teaching.

	who
	===

Me for my students

	why
	===

Because I needed something horribly simple to show the use of named
sections. The name is an Italian joke on "polish", I'd better keep it
unchanged as most of my students are Italian anyways.

	what
	====

An RPN calculator for the  command line: "./povacca 4 5 +". It knows
the following operators:
  "+" and "add" (synonyms) from poadd.c
  "*" and "mul" (synonyms) from pomul.c
  "pop" from popop.c

	how (whow?)
	===========

Using named sections. Definitions of operators live in a separate
.oper section, so the linker juxtaposes all of them in the output
file. A linker script (bigobj.lds) is used to merge this section in
the .data section, and to add named symbols for the start and end of
the .oper array.

The net effect is that you can drop new files in the source directory
to add new operators (you'll need to add the object names to Makefile too).
You'll never need to change pomain.c in order to add operators.


	what's next?
	===========

Nothing. Small examples should remain small. Thanks to Emilio Garcia Cota
for adding "make clean" and ".gitignore", but that's all.

Well... I must add a way to compile this under Windows, as named sections
are useful in a number of contexts. The solution is simple but it took
a while to find, as "ld -r" alone is complaining with gcc for windows.
Marco Pizzamiglio documented the procedure (in Italian) and I'm too
lazy to include it here. Please ask if interested.