}
		if cfg.BuildN || cfg.BuildX {
			sh.ShowCmd("", "ar d %s _cgo_flags", newArchive)
			if cfg.BuildN {
				// TODO(rsc): We could do better about showing the right _cgo_flags even in -n mode.
				// Either the archive is already built and we can read them out,
				// or we're printing commands to build the archive and can
				// forward the _cgo_flags directly to this step.
				return "", nil
			}
		}

'.', that will not be interpreted in unexpected ways. Attempts to use
forbidden characters will get a "malformed #cgo argument" error.

When building, the CGO_CFLAGS, CGO_CPPFLAGS, CGO_CXXFLAGS, CGO_FFLAGS and
CGO_LDFLAGS environment variables are added to the flags derived from
these directives. Package-specific flags should be set using the
directives, not the environment variables, so that builds work in

		}
		return q
	}

	ret := []cfg.EnvVar{
		// Note: Update the switch in runEnv below when adding to this list.
		{Name: "CGO_CFLAGS", Value: join(cflags)},
		{Name: "CGO_CPPFLAGS", Value: join(cppflags)},
		{Name: "CGO_CXXFLAGS", Value: join(cxxflags)},
		{Name: "CGO_FFLAGS", Value: join(fflags)},
		{Name: "CGO_LDFLAGS", Value: join(ldflags)},
		{Name: "PKG_CONFIG", Value: b.PkgconfigCmd()},

	cgoCflags := os.Getenv("CGO_CFLAGS")
	if cgoCflags != "" {
		cgoCflags += " "
	}
	cgoCflags += "-I" + tmpdir

	cgoLdflags := os.Getenv("CGO_LDFLAGS")
	if cgoLdflags != "" {
		cgoLdflags += " "
	}
	cgoLdflags += "-L" + tmpdir + " -ltestgo2c2go"

	goenv := []string{"CGO_CFLAGS=" + cgoCflags, "CGO_LDFLAGS=" + cgoLdflags}

			ctxt.makePathsAbsolute(args, di.Dir)
		}

		switch verb {
		case "CFLAGS":
			di.CgoCFLAGS = append(di.CgoCFLAGS, args...)
		case "CPPFLAGS":
			di.CgoCPPFLAGS = append(di.CgoCPPFLAGS, args...)
		case "CXXFLAGS":
			di.CgoCXXFLAGS = append(di.CgoCXXFLAGS, args...)
		case "FFLAGS":
			di.CgoFFLAGS = append(di.CgoFFLAGS, args...)
		case "LDFLAGS":
			di.CgoLDFLAGS = append(di.CgoLDFLAGS, args...)
		case "pkg-config":

		Does not apply to the CGO_CFLAGS environment variable.
	CGO_CPPFLAGS, CGO_CPPFLAGS_ALLOW, CGO_CPPFLAGS_DISALLOW
		Like CGO_CFLAGS, CGO_CFLAGS_ALLOW, and CGO_CFLAGS_DISALLOW,
		but for the C preprocessor.
	CGO_CXXFLAGS, CGO_CXXFLAGS_ALLOW, CGO_CXXFLAGS_DISALLOW
		Like CGO_CFLAGS, CGO_CFLAGS_ALLOW, and CGO_CFLAGS_DISALLOW,
		but for the C++ compiler.
	CGO_FFLAGS, CGO_FFLAGS_ALLOW, CGO_FFLAGS_DISALLOW

        XTestEmbedFiles    []string // files matched by XTestEmbedPatterns

        // Cgo directives
        CgoCFLAGS    []string // cgo: flags for C compiler
        CgoCPPFLAGS  []string // cgo: flags for C preprocessor
        CgoCXXFLAGS  []string // cgo: flags for C++ compiler
        CgoFFLAGS    []string // cgo: flags for Fortran compiler
        CgoLDFLAGS   []string // cgo: flags for linker

	cmd := exec.Command("go", subcommand)
	cmd.Args = append(cmd.Args, c.goFlags...)
	cmd.Args = append(cmd.Args, args...)
	replaceEnv(cmd, "CGO_CFLAGS", strings.Join(c.cFlags, " "))
	replaceEnv(cmd, "CGO_LDFLAGS", strings.Join(c.ldFlags, " "))
	appendExperimentEnv(cmd, experiments)
	return cmd
}

	cmd := testenv.Command(t, testenv.GoToolPath(t), "build", "-buildmode=c-archive", "-o", ar, lib)
	env := []string{
		"CGO_ENABLED=1",
		"GOOS=ios",
		"GOARCH=arm64",
		"CC=" + strings.Join(CC, " "),
		"CGO_CFLAGS=", // ensure CGO_CFLAGS does not contain any flags. Issue #35459
		"CGO_LDFLAGS=" + strings.Join(CGO_LDFLAGS, " "),
	}
	cmd.Env = append(os.Environ(), env...)
	t.Logf("%q %v", env, cmd)