71db3dc120af os: make SameFile handle paths like c:a.txt properly
ff34a3e84dc0 net: fix CNAME resolving on Windows
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/130250043
Also zsyscall_windows_386.go and zsyscall_windows_amd64.go
have same contents, so merge them into single file.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/124430043
All consts in errors_windows.go (except APPLICATION_ERROR) were
"invented" at the start of windows port to have minimal impact on
existing Go packages. No point keeping them around.
Also remove Errno, since we will be using syscall.Errno everywhere anyway.
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/128290044