fix private_key type documentation in ssh_server_key_api
Fix incorrect reporting of memory on OS X via memsup.

Application memsup should be calculating free memory using the
speculative pages, in the same manner that the Activity Monitor and top
programs on OS X do.  In addition, correct page size to 4096, based on
verification of available memory between top, vm_stat and Activity
Monitor.
Merge branch 'tsloughter/ssh_doc_fix/OTP-11449' into maint

* tsloughter/ssh_doc_fix/OTP-11449:
  fix private_key type documentation in ssh_server_key_api
erts: Add max alignment posix_memalign configure check

On some OSs posix_memalign exists, but it does not allow for alignment
greater than the current page size. So we have to do a runtime check for
alignment size and also add cross compile options.
Merge branch 'lukas/erts/openbsd-posix-memalign-fix/OTP-11371' into maint

* lukas/erts/openbsd-posix-memalign-fix/OTP-11371:
  erts: Add max alignment posix_memalign configure check
Fix client_preferred_next_protocols documentation
Typo fix ambigous -> ambiguous
Update primary bootstrap
Merge branch 'Tonkpils/typo-fix/OTP-11455' into maint

* Tonkpils/typo-fix/OTP-11455:
  Update primary bootstrap
  Typo fix ambigous -> ambiguous
Merge branch 'cmeiklejohn/csm-fix-memsup-problems/OTP-11454' into maint

* cmeiklejohn/csm-fix-memsup-problems/OTP-11454:
  Fix incorrect reporting of memory on OS X via memsup.
Merge branch 'klyr/fix-ssl-npn-doc-2/OTP-11457' into maint

* klyr/fix-ssl-npn-doc-2/OTP-11457:
  Fix client_preferred_next_protocols documentation