sysconf can return -1 on error #569
Description
in posix/src/os-impl-tasks.c sysconf() is used. Its storage is into a type size_t, but sysconf() can return -1. We should change the storage to ssize_t to accommodate this, or we should check for -1 and then store a non-negative value to POSIX_GlobalVars.PageSize. sysconf() shouldn't return -1 when passed _SC_PAGESIZE, so this may be low priority.