cmd/cgo: for -godefs, promote first field of anonymous union

Update issue 6677

When a struct contains an anonymous union, use the type and
name of the first field in the union.

This should make the glibc <sys/resource.h> file work; in that
file struct rusage has fields like

__extension__ union
{
        long int ru_maxrss;
        __syscall_slong_t __ru_maxrss_word;
};

in which the field that matters is ru_maxrss and
__ru_maxrss_word just exists to advance to the next field on
systems where the kernel uses long long fields but userspace
expects long fields.

LGTM=mikioh.mikioh
R=golang-codereviews, mikioh.mikioh
CC=golang-codereviews
https://codereview.appspot.com/106260044

1 files changed, 12 insertions, 0 deletions

diff --git a/misc/cgo/testgodefs/main.go b/misc/cgo/testgodefs/main.go
new file mode 100644
index 000000000..eaf91bc11
--- /dev/null
+++ b/misc/cgo/testgodefs/main.go
@@ -0,0 +1,12 @@
+// Copyright 2014 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// Test that the struct field in anonunion.go was promoted.
+var v1 T
+var v2 = v1.L
+
+func main() {
+}