runtime: add padding to m struct for 64 bit architectures
CL 652276 reduced the m struct by 8 bytes, which has changed the
allocation class on 64 bit OpenBSD platforms. This results in build
failures due to:
M structure uses sizeclass 1792/0x700 bytes; incompatible with mutex flag mask 0x3ff
Add 128 bytes of padding when spinbitmutex is enabled on 64 bit
architectures, moving the size to the half point between the
1792 and 2048 allocation size.
Change-Id: I71623a1f75714543c302217e619d20cf0e717aeb
Reviewed-on: https://go-review.googlesource.com/c/go/+/653335 Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Keith Randall <khr@golang.org>