Signed vs. unsigned pointer warnings

[Timo Sirainen <tss at iki dot fi>]

Are there any other way to enable warning of signed vs. unsigned
pointers than with -pedantic? I think that should deserve a warning
option of it's own, or even be enabled with -Wall or -W.

The annoying thing with -pedantic is that it complains also about %m in
format strings. My program uses them a lot, not just with syslog() but
with other custom printf-like functions which replace %m with strerror()
on the way to vsnprintf.

I see __extension__ helps if I do it separately for every call which
uses %m, but couldn't that be set elsewhere too? For example
__extension__ __attribute__((format, ..)) which would be propagated to
all calls of it	?