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

			if buildmode != "" {
				cmd.Args = append(cmd.Args, "-buildmode", buildmode)
			}
			cmd.Args = append(cmd.Args, dir)
			cmd.Env = append(os.Environ(), env...)
			cmd.Env = append(cmd.Env, "CGO_CFLAGS=") // ensure CGO_CFLAGS does not contain any flags. Issue #35459
			cmd.Env = append(cmd.Env, "LINK_TEST_TOOLEXEC=1")
			out, err := cmd.CombinedOutput()
			if err != nil {
				t.Fatalf("go build -o %v %v: %v\n%s", exe, dir, err, out)

//
//   - -buildmode: the buildmode flag used (typically "exe")
//   - -compiler: the compiler toolchain flag used (typically "gc")
//   - CGO_ENABLED: the effective CGO_ENABLED environment variable
//   - CGO_CFLAGS: the effective CGO_CFLAGS environment variable
//   - CGO_CPPFLAGS: the effective CGO_CPPFLAGS environment variable
//   - CGO_CXXFLAGS:  the effective CGO_CXXFLAGS environment variable

 */
struct cgoTracebackArg {
	uintptr_t  Context;
	uintptr_t  SigContext;
	uintptr_t* Buf;
	uintptr_t  Max;
};

/*
 * TSAN support.  This is only useful when building with
 *   CGO_CFLAGS="-fsanitize=thread" CGO_LDFLAGS="-fsanitize=thread" go install
 */
#undef CGO_TSAN
#if defined(__has_feature)
# if __has_feature(thread_sanitizer)
#  define CGO_TSAN
# endif
#elif defined(__SANITIZE_THREAD__)

stderr 'invalid flag in #cgo CFLAGS: -D @foo'

# Reject #cgo CFLAGS -D@foo
cp y_cflags_dash_d_at_foo.txt y.go
! go build x
stderr 'invalid flag in #cgo CFLAGS: -D@foo'

# Check for CFLAGS in commands
env CGO_CFLAGS=-D@foo
cp y_no_cflags.txt y.go
go build -n x
stderr '-D@foo'

-- go.mod --
module x

go 1.16
-- x_gc.go.txt --
package x

//go:cgo_ldflag "-fplugin=foo.so"

import "C"

		if strings.Contains(testenv.Builder(), "clang") {
			extraLDFlags += " -fuse-ld=lld"
		}
		const cflags = "-flto -Wno-lto-type-mismatch -Wno-unknown-warning-option"
		cmd.Env = append(cmd.Environ(),
			"CGO_CFLAGS="+cflags,
			"CGO_CXXFLAGS="+cflags,
			"CGO_LDFLAGS="+cflags+extraLDFlags)
	}
	out, err := cmd.CombinedOutput()
	if string(out) != "OK\n" {
		t.Errorf("%s", string(out))
	}
	if err != nil {

		t.Run(cflags, func(t *testing.T) {
			testenv.MustHaveGoBuild(t)
			testenv.MustHaveCGO(t)
			t.Parallel()

			cmd := exec.Command("go", "build", path("issue14669.go"))
			cmd.Env = append(os.Environ(), "CGO_CFLAGS="+cflags)
			out, err := cmd.CombinedOutput()
			if err != nil {
				t.Errorf("%#q: %v:\n%s", strings.Join(cmd.Args, " "), err, out)
			}
		})
	}
}

func TestMallocCrashesOnNil(t *testing.T) {

		}

		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...)

//		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