all: replace execabs with os/exec

os/exec no longer searches executablse in the current directory as of
Go 1.19. See https://go.dev/blog/path-security and https://go.dev/issue/43724.

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().
 	_ "github.com/ebitengine/gomobile/geom"
-	exec "golang.org/x/sys/execabs"
 )
 
 //go:embed gobind.go

cmd/ebitenmobile/main.go

@@ -27,12 +27,12 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"strings"
 	"text/template"
 	"unicode"
 
-	exec "golang.org/x/sys/execabs"
 	"golang.org/x/tools/go/packages"
 )
 

internal/png/gen.go

@@ -23,13 +23,13 @@ import (
 	"go/parser"
 	"go/token"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
 
-	exec "golang.org/x/sys/execabs"
 	"golang.org/x/tools/go/ast/astutil"
 )
 

internal/processtest/processtest_test.go

@@ -20,14 +20,13 @@ import (
 	"bytes"
 	"context"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"sync"
 	"testing"
 	"time"
-
-	exec "golang.org/x/sys/execabs"
 )
 
 func isWSL() (bool, error) {