cmd/cgo: error on multiple incompatible function declarations

When there are multiple declarations of a function, ensure that
those declarations at least agree on the size/alignment of arguments
and return values.

It's hard to be stricter given existing code and situations where
arguments differ only by typedefs. For instance:
    int usleep(unsigned);
    int usleep(useconds_t);

Fixes #67699.

Change-Id: I3b4b17afee92b55f9e712b4590ec608ab1f7ac91
Reviewed-on: https://go-review.googlesource.com/c/go/+/588977
Auto-Submit: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

0 files changed, 0 insertions, 0 deletions