go: x/mobile/cmd/gomobile: gomobile build on simple program returns "ld: error: duplicate symbol: x_cgo_inittls"

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

$ go version
go version go1.15.5 linux/amd64

Does this issue reproduce with the latest release?

Yes, latest release is 1.15.5

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

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/nicklas/.cache/go-build"
GOENV="/home/nicklas/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/nicklas/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/nicklas/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
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 -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build465769179=/tmp/go-build -gno-record-gcc-switches"

What did you do?

run gomobile build on a simple script like:

package main

/*
double Square(double a)
{
    return a * a;
}
*/
import "C"
import "fmt"

func main() {
    a := C.double(10)
    b := C.Square(a)
    fmt.Println(b)
}

What did you expect to see?

That the process succeeded

What did you see instead?

ld: error: duplicate symbol: x_cgo_inittls
>>> defined at gcc_android.c:90
>>>            $WORK/b059/_x003.o:(x_cgo_inittls)
>>> defined at gcc_linux_arm.c:13
>>>            $WORK/b059/_x006.o:(.bss+0x4)
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I think this comes from latest NDK upgrade

I have had a quite hard time to prove that the ndk is at least part of the issue since ndk-bundle precedence is hard coded in env.go https://github.com/golang/mobile/blob/973feb4309de5c3aad0553fc987d76abf1fa58f7/cmd/gomobile/env.go#L181

So I renamed ndk-bundle folder temporary so I could change ndk with ANDROID_NDK_HOME

Then:

export ANDROID_NDK_HOME=$ANDROID_HOME/ndk/22.0.6917172
gomobile build -x -v

fails with the error in this issue

but this works without issue:

export ANDROID_NDK_HOME=$ANDROID_HOME/ndk/21.3.6528147
gomobile build -x -v

and

export ANDROID_NDK_HOME=$ANDROID_HOME/ndk/20.0.5594570
gomobile build -x -v

By using the -x flag I could confirm that the older NDK then was used instead of ndk-bundle.

This issue was also mentioned in https://github.com/golang/go/issues/42647#issuecomment-728608953