Hello,
this patch extends libauparse to support arbitrary boolean expressions 
and searching for record type ranges.

It seems best to define expression syntax and add a single 
ausearch_add_expression() call, rather than build the expression from 
atomic subexpressions.  The defined syntax could be shared by all tools 
that link to libauparse, and programs would be able to run (and display 
meaningful error messages, as opposed to crashing when a relocation can 
not be resloved) even if the installed libauparse version does not 
support the used filter.

Attached is a description of the expression syntax.  Please check 
whether the design is reasonably future-proof.  A nicer alternative to 
using three different sets of comparison operators would be welcome.
	Mirek