SlackBuildsOrg/development/cproto

cproto (generate function prototypes for C code)

Cproto is a program that generates function prototypes and
variable declarations from C source code. It can also convert
function definitions between the old style and the ANSI C style.
This conversion overwrites the original files, so make a backup copy
of your files in case something goes wrong.

The program isn't confused by complex function definitions as much as
other prototype generators because it uses a yacc generated parser.