all: use x/sys/execabs instead of os/exec

Closes #2418

cmd/ebitenmobile/gobind.go

@@ -23,10 +23,10 @@ import (
 	"fmt"
 	"log"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"strings"
 
+	exec "golang.org/x/sys/execabs"
 	"golang.org/x/tools/go/packages"
 )
 

cmd/ebitenmobile/gomobile.go

@@ -18,13 +18,13 @@ import (
 	_ "embed"
 	"fmt"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"runtime"
 	"runtime/debug"
 
 	// Add a dependency on gomobile in order to get the version via debug.ReadBuildInfo().
 	_ "golang.org/x/mobile/geom"
+	exec "golang.org/x/sys/execabs"
 )
 
 //go:embed gobind.go

cmd/ebitenmobile/main.go

@@ -25,11 +25,11 @@ import (
 	"fmt"
 	"log"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"strings"
 	"text/template"
 
+	exec "golang.org/x/sys/execabs"
 	"golang.org/x/tools/go/packages"
 )