Created attachment 72881 [details] [review]
Introduce and use CPH_PATH_MAX

Hi,

when building cups-pk-helper >= 0.2.3 on GNU/Hurd, it fails like this:

| make[3]: Entering directory `$SRCDIR/src'
|   CC     cups_pk_helper_mechanism-cups.o
| cups.c: In function ‘_cph_cups_prepare_ppd_for_options’:
| cups.c:2394:34: error: ‘PATH_MAX’ undeclared (first use in this function)
| cups.c:2394:34: note: each undeclared identifier is reported only once for each | function it appears in
| cups.c:2394:23: warning: unused variable ‘newppdfile’ [-Wunused-variable]
| make[3]: *** [cups_pk_helper_mechanism-cups.o] Error 1

this happens because PATH_MAX is an optional constant in POSIX, and the Hurd does not provide it on purpose.

Unfortunately, the cups API used just wants a char* buffer and its size [*], so all we can do is just passing a buffer large enough; I've defined CPH_PATH_MAX to be PATH_MAX if available (or 1024 if not).

[*] not even checking internally the buffer is large enough for the job, merely truncating it at the passed size...