// build C code (if any) and link with Go code
			cmd, err := cc(config.cFlags...)
			if err != nil {
				t.Fatalf("error running cc: %v", err)
			}
			cmd.Args = append(cmd.Args, config.ldFlags...)
			cmd.Args = append(cmd.Args, "-o", outPath, "-I", dir.Base())
			if tc.cSrc != "" {
				cmd.Args = append(cmd.Args, srcPath(tc.cSrc))
			}

	fp_flags int32
	fp_pad   int32
}

type mcontext struct {
	mc_gpregs gpregs
	mc_fpregs fpregs
	mc_flags  int32
	mc_pad    int32
	mc_spare  [8]uint64
}

type ucontext struct {
	uc_sigmask  sigset
	uc_mcontext mcontext
	uc_link     *ucontext
	uc_stack    stackt
	uc_flags    int32
	__spare__   [4]int32
	pad_cgo_0   [12]byte
}

type timespec struct {
	tv_sec  int64

	mc_r12           uint64
	mc_r13           uint64
	mc_r14           uint64
	mc_r15           uint64
	mc_trapno        uint32
	mc_fs            uint16
	mc_gs            uint16
	mc_addr          uint64
	mc_flags         uint32
	mc_es            uint16
	mc_ds            uint16
	mc_err           uint64
	mc_rip           uint64
	mc_cs            uint64
	mc_rflags        uint64
	mc_rsp           uint64

			cmdline := []string{"build", "-gcflags", "-S=2"}

			// Append flags, but don't override -gcflags=-S=2; add to it instead.
			for i := 0; i < len(flags); i++ {
				flag := flags[i]
				switch {
				case strings.HasPrefix(flag, "-gcflags="):
					cmdline[2] += " " + strings.TrimPrefix(flag, "-gcflags=")
				case strings.HasPrefix(flag, "--gcflags="):

					Directives: p.Internal.Build.XTestDirectives,
				},
				Imports:    ximports,
				RawImports: rawXTestImports,

				Asmflags:       p.Internal.Asmflags,
				Gcflags:        p.Internal.Gcflags,
				Ldflags:        p.Internal.Ldflags,
				Gccgoflags:     p.Internal.Gccgoflags,
				Embed:          xtestEmbed,
				OrigImportPath: p.Internal.OrigImportPath,
				PGOProfile:     p.Internal.PGOProfile,
			},
		}

		t.Fatalf("failed to create mod file: %v", err)
	}

	// As of 2018-07-17, lldb doesn't support compressed DWARF, so
	// disable it for this test.
	cmd := exec.Command(testenv.GoToolPath(t), "build", "-gcflags=all=-N -l", "-ldflags=-compressdwarf=false", "-o", "a.exe")
	cmd.Dir = dir
	cmd.Env = append(os.Environ(), "GOPATH=") // issue 31100
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("building source %v\n%s", err, out)

		}
		if load.BuildLdflags.Present() {
			fmt.Println("go build: when using gccgo toolchain, please pass linker flags using -gccgoflags, not -ldflags")
		}
	case "gc":
		if load.BuildGccgoflags.Present() {
			fmt.Println("go build: when using gc toolchain, please pass compile flags using -gcflags, and linker flags using -ldflags")
		}
	}

	depMode := ModeBuild

/*
// intentionally write the same LDFLAGS differently
// to test correct handling of LDFLAGS.
#cgo linux LDFLAGS: -L. -lcgosotest
#cgo dragonfly LDFLAGS: -L. -l cgosotest
#cgo freebsd LDFLAGS: -L. -l cgosotest
#cgo openbsd LDFLAGS: -L. -l cgosotest
#cgo solaris LDFLAGS: -L. -lcgosotest
#cgo netbsd LDFLAGS: -L. libcgosotest.so
#cgo darwin LDFLAGS: -L. libcgosotest.dylib
#cgo windows LDFLAGS: -L. libcgosotest.a

		t.Fatal(err)
	}

	// Link with -v -linkmode=external to see the flags we pass to the
	// external linker.
	ldflags := "-ldflags=-v -linkmode=external -tmpdir=" + linktmp
	var out0 []byte
	for i := 0; i < 5; i++ {
		cmd := testenv.Command(t, testenv.GoToolPath(t), "build", ldflags, "-o", exe, src)
		out, err := cmd.CombinedOutput()
		if err != nil {
			t.Fatalf("build failed: %v, output:\n%s", err, out)
		}

//sys	Dup2(from int, to int) (err error)
//sys	dup3(from int, to int, flags int) (err error)
//sys	Fchdir(fd int) (err error)
//sys	Fchflags(fd int, flags int) (err error)
//sys	Fchmod(fd int, mode uint32) (err error)
//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Flock(fd int, how int) (err error)
//sys	Fpathconf(fd int, name int) (val int, err error)
//sys	Fstat(fd int, stat *Stat_t) (err error)