Whoa, that does not work. Switching to 64bit time_t for perl means that all perl modules will also get the 64bit time_t. The problem is that this changes the ABI for some non-perl libraries. For example, interfacing with BerkeleyDB will no longer work as it has a time_t before the function jump table. This means if the BerkeleyDB library is compiled with 32bit time_t calls from a 64bit time_t compilation will segfault in funny ways. (Took me some time to debug this issue.) So it seems it is either the complete distribution switching to 64bit time_t or no package at all. What I can do is to change the way the perl interpreter struct is defined so that the size matches both for 32bit and 64bit time_t. With that done, interfacing from a 64bit time_t program should work so that the check in pcp's configure script can be removed.