I figured this would be useful:

/home/guido/p25/Modules/_ctypes/libffi/src/x86/ffi.c:177: warning:
function declaration isn't a prototype
/home/guido/p25/Modules/_ctypes/libffi/src/x86/ffi.c:194: warning:
function declaration isn't a prototype
/home/guido/p25/Modules/unicodedata.c: In function `unicodedata_decimal':
/home/guido/p25/Modules/unicodedata.c:110: warning: `rc' might be used
uninitialized in this function
/home/guido/p25/Modules/unicodedata.c: In function `unicodedata_numeric':
/home/guido/p25/Modules/unicodedata.c:197: warning: `rc' might be used
uninitialized in this function
/home/guido/p25/Modules/readline.c: In function `flex_complete':
/home/guido/p25/Modules/readline.c:681: warning: implicit declaration of
function `completion_matches'
/home/guido/p25/Modules/readline.c:681: warning: return makes pointer
from integer without a cast
/home/guido/p25/Modules/cjkcodecs/_codecs_iso2022.c: In function
`iso2022processesc':
/home/guido/p25/Modules/cjkcodecs/_codecs_iso2022.c:307: warning:
`esclen' might be used uninitialized in this function

2.96 is ancient and I don't see those warnings with 4.x series. Can I
close this bug?

With a newer compiler (GCC 4.0.1 on OSX 10.5.1) I still get some warnings:

/Users/guido/p25/Modules/_ctypes/libffi/src/x86/ffi_darwin.c:220:
warning: function declaration isn’t a prototype

/Users/guido/p25/Modules/readline.c: In function ‘flex_complete’:
/Users/guido/p25/Modules/readline.c:681: warning: implicit declaration
of function ‘completion_matches’
/Users/guido/p25/Modules/readline.c:681: warning: return makes pointer
from integer without a cast

This is with GNU readline 5.2.

Let's make this a catch-all bug to remind us to ensure the build is
warning-free on as many platforms as possible.

While we're at it, see 2388.

Is this still a problem?

Let someone else review this.