if cppflags, err = buildFlags("CPPFLAGS", "", p.CgoCPPFLAGS, checkCompilerFlags); err != nil {
		return
	}
	if cflags, err = buildFlags("CFLAGS", DefaultCFlags, p.CgoCFLAGS, checkCompilerFlags); err != nil {
		return
	}
	if cxxflags, err = buildFlags("CXXFLAGS", DefaultCFlags, p.CgoCXXFLAGS, checkCompilerFlags); err != nil {
		return
	}

//	    CgoEnabled    bool     // whether cgo can be used
//	    UseAllFiles   bool     // use files regardless of //go:build lines, file names
//	    Compiler      string   // compiler to assume when computing target paths
//	    BuildTags     []string // build constraints to match in //go:build lines
//	    ToolTags      []string // toolchain-specific build constraints
//	    ReleaseTags   []string // releases the current release is compatible with

	}
	if cfg.BuildMSan {
		appendSetting("-msan", "true")
	}
	// N.B. -pgo added later by setPGOProfilePath.
	if cfg.BuildRace {
		appendSetting("-race", "true")
	}
	if tags := cfg.BuildContext.BuildTags; len(tags) > 0 {
		appendSetting("-tags", strings.Join(tags, ","))
	}
	if cfg.BuildTrimpath {
		appendSetting("-trimpath", "true")
	}
	if p.DefaultGODEBUG != "" {