MFC	r258017, r258429, r258748, r258817:

Merge updates from FSF pre4.3 GCC inspired on Apple's gcc:

  Updates to libiberty and mangling.
  New align attribute.
  Merge Apple updates to libstdc++.
MFC	r258651, r258943:
gcc: Altivec register adjustments from Apple.
gcc: On rs6000 update sp_offset depending only on size.

Tested by:		Justin Hibbits
Obtained from:		gcc pre-4.3 (rev. 124763, 125116; GPLv2)
MFC r259108:
When comparing device IDs, make sure that they have the same type
(like NAA assigned) and identify the same entity (like device or port).
Otherwise there can be false positives since at least some models of
Seagate disks use same IDs for the whole device and one of its ports.
Direct Commit of mountroot> prompt fix r259748 (since there's no sane
branching relationship between that branch and this one and since the
more general fix in head may be too risky for a stbale branch this
mature):

 Fix mountroot> prompt eating most of the characters by not enabling
 RXRDY interrupts in the attach routine. Instead, defer this until the
 first interrupt we see after the device is opened. Given the console
 use case, we're guaranteed to get a TXRDY interrupt before any reads
 are posted due to boot messages, which makes this work.

 The real fix is to use cngrab/cnungrab function pointers to disable
 RXRDY interrupts while grabbed. However, that touches the MI uart
 code, so was disallowed for 10.0 due to the lateness of the hour this
 fix was proposed. It works for mountroot, the most common atmel kernel
 prompt use cases, but wouldn't work for GELI since it prompts later in
 the boot process.
[automated] Merge in upstream-github/stable/9