Bug 925319 - delete HAVE_U?INT* checks from configure; r=glandium
Bug 925173 - don't depend on HAVE_64BIT_OS in FileUtils.cpp; use the standard __LP64__ macro instead; r=bsmedberg

This point in the code is Mac-specific, so we are free to use Mac-specific macros
here.  Just use __LP64__ instead of HAVE_64BIT_OS.
Bug 925169 - part 1 - don't use MOZ_MEMORY_SIZEOF_PTR_2POW in jemalloc.c; r=glandium
Bug 925169 - part 2 - delete MOZ_MEMORY_SIZEOF_PTR_2POW from configury; r=glandium
Bug 925222 - part 1 - just check for __linux__ in nsUserInfo::GetDomain; r=bsmedberg

Linux's libc (with _GNU_SOURCE, which we use) and bionic are the only
interesting libcs that define domainname.  The BSDs and OSX don't, and
the latter is the only one we really need to care about.  Since we're
doing multiple configure checks for this one (!) place, it's not really
worth worrying about.  Let's just hardcode this check and be done with
it.
Bug 925222 - part 2 - delete configure checks for domainname member of struct utsname; r=glandium
Bug 925330 - don't use HAVE_64BIT_OS when building elfhack; r=glandium
Bug 925334 - delete check for HAVE_GNU_GET_LIBC_VERSION; r=glandium