make.bash: fix old builds

Fixes #3222.

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5761044

diff --git a/src/make.bash b/src/make.bash
index aaee75e460faa5d0c9c436bcdfc7bc2f31a2eb64..3668e92046d49a6b15dd529d8f3d3ec1e7449b5a 100755 (executable)
--- a/src/make.bash
+++ b/src/make.bash
@@ -76,6 +76,9 @@ do
        fi
 done
 
+# Clean old generated file that will cause problems in the build.
+rm -f ./pkg/runtime/runtime_defs.go
+
 # Finally!  Run the build.
 
 echo '# Building C bootstrap tool.'