diff --git a/go/ssa/interp/external.go b/go/ssa/interp/external.go
index fc43366a00..627aa5a81e 100644
--- a/go/ssa/interp/external.go
+++ b/go/ssa/interp/external.go
@@ -79,6 +79,7 @@ func init() {
 		"math.Log":                         ext۰math۰Log,
 		"math.Min":                         ext۰math۰Min,
 		"os.runtime_args":                  ext۰os۰runtime_args,
+		"os.runtime_beforeExit":            ext۰os۰runtime_beforeExit,
 		"reflect.New":                      ext۰reflect۰New,
 		"reflect.SliceOf":                  ext۰reflect۰SliceOf,
 		"reflect.TypeOf":                   ext۰reflect۰TypeOf,
@@ -228,6 +229,10 @@ func ext۰os۰runtime_args(fr *frame, args []value) value {
 	return fr.i.osArgs
 }
 
+func ext۰os۰runtime_beforeExit(fr *frame, args []value) value {
+	return nil
+}
+
 func ext۰runtime۰Breakpoint(fr *frame, args []value) value {
 	runtime.Breakpoint()
 	return nil
@@ -328,7 +333,9 @@ func ext۰sync۰runtime_Semrelease(fr *frame, args []value) value {
 }
 
 func ext۰runtime۰GOMAXPROCS(fr *frame, args []value) value {
-	return runtime.GOMAXPROCS(args[0].(int))
+	// Ignore args[0]; don't let the interpreted program
+	// set the interpreter's GOMAXPROCS!
+	return runtime.GOMAXPROCS(0)
 }
 
 func ext۰runtime۰Goexit(fr *frame, args []value) value {