Most warnings are for functions implicitly returning int. Change most
of these functions to return void. (Traditional K&R C had no void
type, but C89 has it.)
Add prototypes to most function declarations in headers. This is
easy, because ego declares most of its extern functions, and the
comments listed most parameters. There were a few outdated or missing
declarations, and a few .c files that failed to include an .h with the
declarations.
Add prototypes to a few function definitions in .c files. Most
functions still have traditional K&R definitions. Most STATIC
functions still don't have prototypes, because they have no earlier
declaration where I would have added the prototype.
Change some prototypes in util/ego/share/alloc.h. Functions newmap()
and oldmap() handle an array of pointers to something; change the
array's type from `short **` to `void **`. Callers use casts to go
between `void **` and the correct type, like `line_p *`. Function
oldtable() takes a `short *`, not a `short **`; I added the wrong type
in 5bbbaf4.
Make a few other changes to silence warnings. There are a few places
where clang wants extra parentheses in the code.
Edit util/ego/ra/build.lua to add the missing dependency on ra*.h; I
needed this to prevent crashes from ra.
Enable this in CS for PowerPC; disable it for all other machines.
PowerPC has no remainder instruction; the back end uses division to
compute remainder. If CS finds both a / b and a % b, then CS now
rewrites a % b as a - b * (a / b) and computes a / b only once. This
removes an extra division in the PowerPC code, so it saves both time
and space.
I have not considered whether to enable this optimization for other
machines. It might be less useful in machines with a remainder
instruction. Also, if a % b occurs before a / b, the EM code gets a
DUP. PowerPC ncg handles this DUP well; other back ends might not.
