What version of Go are you using (go version)?

$ go version
go version devel +8f2db14cd3 Tue Nov 10 18:42:47 2020 +0000 linux/amd64

Does this issue reproduce with the latest release?

No. It was introduced in CL 258938.

What did you do?

Build the following:

package p

// typedef struct { } T;
import "C"

//export F
func F(C.T) {}

(There are other types for which the failure is the same, such as struct { int x[0]; }.)

What did you expect to see?

Successful build.

What did you see instead?

_cgo_export.c: In function ‘F’:
_cgo_export.c:175:58: error: excess elements in struct initializer [-Werror]
  175 |  } __attribute__((__packed__, __gcc_struct__)) _cgo_a = {0};
      |                                                          ^
_cgo_export.c:175:58: note: (near initialization for ‘_cgo_a.p0’)

Thanks to @cherrymui for tracking this down and creating the reproducer.