[lld] r249760 - [ELF2] Make the system page size a target-dependent property

[Rafael Espíndola via llvm-commits]

> I added a comment in r250087. To be honest, I don't understand myself why this is necessary, as I agree the underlying system page size is smaller, but experimentally, this is certainly necessary to get the loader to set the memory permissions correctly. Also, this matches what ld.gold does.

Thanks. For what it is worth, the first item (ld.so being happy) is a
reasonable requirement, the second one not so much. "Cargo coding" can
lead to old bugs (or no longer relevant issues) propagating to new
software.

Thanks,
Rafael