this came up because lld changed tls alignment on aarch64 as a
workaround for a bionic abi issue https://reviews.llvm.org/D53906
but lld does not handle p_vaddr%p_align!=0 right so it broke on glibc
https://reviews.llvm.org/D61824

the patch is untested (bfd linker cannot seem to create problematic
elf objects), but at least there are no regressions with libc-test.