A program that takes as input a series of C source files
 and produces a LaTeX or HTML document containing a cross
 reference of the files/functions/variables in the program,
 including documentation taken from suitably formatted
 source code comments.
 The documentation is stored in the C source file in
 specially formatted comments, making it simple to maintain.
 The cross referencing includes lists of functions called,
 callers of each function, usage of global variables, header
 file inclusion, macro definitions and type definitions.
 Works for ANSI C, including many gcc extensions.