func defaultCCIsAbsolute(s *script.State) (bool, error) {
	GOOS, _ := s.LookupEnv("GOOS")
	GOARCH, _ := s.LookupEnv("GOARCH")
	defaultCC := cfg.DefaultCC(GOOS, GOARCH)
	if filepath.IsAbs(defaultCC) {
		if _, err := exec.LookPath(defaultCC); err == nil {
			return true, nil
		}
	}
	return false, nil
}

func ccIs(s *script.State, want string) (bool, error) {
	CC, _ := s.LookupEnv("CC")
	if CC != "" {
		return CC == want, nil
	}

		"testO2",
		func(out, src string) []string {
			return []string{"gcc", "-shared", "-s", "-Werror", "-o", out, "-O2", src}
		},
	},
}

func TestStdcallAndCDeclCallbacks(t *testing.T) {
	if _, err := exec.LookPath("gcc"); err != nil {
		t.Skip("skipping test: gcc is missing")
	}
	tmp := t.TempDir()

	oldRegs := runtime.SetIntArgRegs(abi.IntArgRegs)
	defer runtime.SetIntArgRegs(oldRegs)

//	FromToolchain("invalid") == ""
func FromToolchain(name string) string {
	if strings.ContainsAny(name, "\\/") {
		// The suffix must not include a path separator, since that would cause
		// exec.LookPath to resolve it from a relative directory instead of from
		// $PATH.
		return ""
	}

	var v string
	if strings.HasPrefix(name, "go") {
		v = name[2:]
	} else {
		return ""
	}

		err = cmd.Wait()
		return stdoutBuf.String(), stderrBuf.String(), err
	}
	return wait, nil
}

// lookPath is (roughly) like exec.LookPath, but it uses the script's current
// PATH to find the executable.
func lookPath(s *State, command string) (string, error) {
	var strEqual func(string, string) bool
	if runtime.GOOS == "windows" || runtime.GOOS == "darwin" {

stderr '# runtime/cgo\nGO_BREAK_CLANG is set'

-- go.mod --
module example/issue64423
go 1.20
-- which/main.go --
package main

import (
	"os"
	"os/exec"
)

func main() {
	path, err := exec.LookPath(os.Args[1])
	if err != nil {
		panic(err)
	}
	os.Stdout.WriteString(path)
}
-- fakeclang/main.go --
package main

import (
	"bufio"
	"bytes"
	"log"
	"os"
	"os/exec"
	"path/filepath"

			os.Exit(0)
		}
		return err
	}

	// Use the original binary location. This works with symlinks such that if
	// the file it points to has been changed we will use the updated symlink.
	argv0, err := exec.LookPath(os.Args[0])
	if err != nil {
		return err
	}

	// Invokes the execve system call.
	// Re-uses the same pid. This preserves the pid over multiple server-respawns.
	return syscall.Exec(argv0, os.Args, os.Environ())

			goBuildErr = fmt.Errorf("%v: %w", cmd, err)
			return
		}
		out = bytes.TrimSpace(out)
		if len(out) == 0 {
			goBuildErr = fmt.Errorf("%v: no tool reported", cmd)
			return
		}
		if _, err := exec.LookPath(string(out)); err != nil {
			goBuildErr = err
			return
		}

		if platform.MustLinkExternal(runtime.GOOS, runtime.GOARCH, false) {
			// We can assume that we always have a complete Go toolchain available.

	})
	// The first call will skip t with a nice message. On later calls, we just skip.
	if !haveSwig {
		t.Skip("swig not found")
	}
}

func mustHaveSwigOnce(t *testing.T) {
	swig, err := exec.LookPath("swig")
	if err != nil {
		t.Skipf("swig not in PATH: %s", err)
	}

	// Check that swig was installed with Go support by checking
	// that a go directory exists inside the swiglib directory.

	"strings"
	"testing"
)

func TestFortran(t *testing.T) {
	testenv.MustHaveGoRun(t)
	testenv.MustHaveCGO(t)

	// Find the FORTRAN compiler.
	fc := os.Getenv("FC")
	if fc == "" {
		fc, _ = exec.LookPath("gfortran")
	}
	if fc == "" {
		t.Skip("fortran compiler not found (try setting $FC)")
	}

	var fcExtra []string
	if strings.Contains(fc, "gfortran") {

// executable.
func CachedExec() script.Cond {
	return script.CachedCondition(
		"<suffix> names an executable in the test binary's PATH",
		func(name string) (bool, error) {
			_, err := cfg.LookPath(name)
			return err == nil, nil
		})