runtime: deduplicate Windows stdcall

There is no need to have a dedicated stdcall variant for each
number of arguments. Instead, we can use a variadic function
that accepts any number of arguments and handles them uniformly.

While here, improve documentation of syscall_syscalln to make it clear
that it should not be used within the runtime package.

Change-Id: I022afc7f28d969fd7307bb2b1f4594246ac38d18
Reviewed-on: https://go-review.googlesource.com/c/go/+/691215
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Mark Freeman <mark@golang.org>

0 files changed, 0 insertions, 0 deletions