compiler: add support for CGO_ENABLED environment variable

goenv/goenv.go

@@ -18,6 +18,7 @@ var Keys = []string{
 	"GOROOT",
 	"GOPATH",
 	"GOCACHE",
+	"CGO_ENABLED",
 	"TINYGOROOT",
 }
 
@@ -57,6 +58,13 @@ func Get(name string) string {
 			panic("could not find cache dir: " + err.Error())
 		}
 		return filepath.Join(dir, "tinygo")
+	case "CGO_ENABLED":
+		val := os.Getenv("CGO_ENABLED")
+		if val == "1" || val == "0" {
+			return val
+		}
+		// Default to enabling CGo.
+		return "1"
 	case "TINYGOROOT":
 		return sourceDir()
 	default: