--- a/src/pkg/runtime/Makefile
+++ b/src/pkg/runtime/Makefile
@@ -129,7 +129,7 @@ mkversion: mkversion.c
 	quietgcc -o $@ -I "$(GOROOT)/include" $< "$(GOROOT)/lib/lib9.a"
 
 version.go: mkversion
-	./mkversion >version.go
+	GOROOT=$(QUOTED_GOROOT_FINAL) ./mkversion >version.go
 
 version_$(GOARCH).go:
 	(echo 'package runtime'; echo 'const theGoarch = "$(GOARCH)"') >$@
--- a/src/Make.inc
+++ b/src/Make.inc
@@ -82,6 +82,7 @@ export GOARCH GOOS GOHOSTARCH GOHOSTOS
 nullstring :=
 space := $(nullstring) # a space at the end
 QUOTED_GOROOT:=$(subst $(space),\ ,$(GOROOT))
+QUOTED_GOROOT_FINAL:=$(subst $(space),\ ,$(GOROOT_FINAL))
 
 # default GOBIN
 ifndef GOBIN