x/mobile: gomobile cross-device link error on final .app mv

[kettek]

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

$ go version
go version go1.12.4 darwin/amd64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/kts/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/kts/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/m_/fjkzltc90_53qbckvq23bync0000gn/T/go-build675724674=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Ran gomobile build -target ios.

The full command I ran is env __IPHONEOS__=1 env CGO_CPPFLAGS="-I/usr/local/include/SDL2/ -DSDL_DISABLE_IMMINTRIN_H=1 -DTARGET_OS_IPHONE -D__IPHONEOS__" gomobile build -target=ios/arm -tags static -x -v -bundleid net.kettek.gosdlrender but this is inconsequential to the reason why the failure occurred.

What did you expect to see?

A successful mv operation before removal of the $WORK directory.

What did you see instead?

** BUILD SUCCEEDED **

mv $WORK/build/Release-iphoneos/main.app render.app
rm -r -f "$WORK"
gomobile: rename /var/folders/m_/fjkzltc90_53qbckvq23bync0000gn/T/gomobile-work-342798608/build/Release-iphoneos/main.app render.app: cross-device link

** The cross-device link error, as far as I know, has to do with the fact my root partition is on a different filesystem than my Users partition -- the root is HFS+ and the Users is ZFS. This should be fixable by issuing a cp command rather than a mv. **

[bcmills]

CC @hyangah