5c, 5g, 8c, 8g: make 64-bit fields 64-bit aligned

[dvyukov]

64-bit load/store functions on 386 assume that the addr is 64-bit aligned, but 8g does
not ensure that.
See also issue https://golang.org/issue/3798

[rsc]

Comment 1:

5c, 5g, 8c, 8g: make 64-bit fields 64-bit aligned
This is necessary for atomics to work correctly.

Labels changed: added priority-soon, removed priority-triage.

Owner changed to @rsc.

[minux]

Comment 2:

do we need to increase Structrnd and maxround from sizeof(uintptr) to 8 also?

[rsc]

Comment 3:

Issue #3798 has been merged into this issue.

[rsc]

Comment 4:

Status changed to Duplicate.

Merged into issue #599.

[rsc]

Comment 5:

Labels changed: added go1.1.