cmd/cgo: iterate over names in deterministic order
This makes GCC behavior (and cgo build failures) deterministic.
Fixes #8487.
Ran this shell command on linux/amd64 (Ubuntu 12.04) before and
after this change:
for x in `seq 100`; do
go tool cgo -debug-gcc=true issue8441.go 2>&1 | md5sum
done | sort | uniq -c
Before:
67
2cdcb8c7c4e290f7d9009abc581b83dd -
10
9a55390df94f7cec6d810f3e20590789 -
10
acfad22140d43d9b9517bbc5dfc3c0df -
13
c337f8fee2304b3a8e3158a4362d8698 -
After:
100
785c316cbcbcd50896695050e2fa23c1 -
LGTM=minux, iant
R=golang-codereviews, bradfitz, minux, iant
CC=golang-codereviews
https://golang.org/cl/
126990043