go-cloud: all: build fails on darwin

Describe the bug

Building things that use this library seems to yield an error on darwin, both amd64 and arm64.

Example output:

❯ GOOS=darwin GOARCH=arm64 go build .
# github.com/mattn/go-ieproxy
../../Go/pkg/mod/github.com/mattn/go-ieproxy@v0.0.3/ieproxy.go:36:9: undefined: getConf
../../Go/pkg/mod/github.com/mattn/go-ieproxy@v0.0.3/ieproxy.go:41:9: undefined: reloadConf
../../Go/pkg/mod/github.com/mattn/go-ieproxy@v0.0.3/ieproxy.go:48:2: undefined: overrideEnvWithStaticProxy
../../Go/pkg/mod/github.com/mattn/go-ieproxy@v0.0.3/ieproxy.go:53:13: psc.findProxyForURL undefined (type *ProxyScriptConf has no field or method findProxyForURL, but does have FindProxyForURL)

To Reproduce

GOOS=darwin GOARCH=arm64 go build .

Expected behavior

Build just fine.

Version

0.25.

Additional context

v0.24 works fine. It seems that its related to the update of go-ieproxy to v0.0.3.