diff --git a/imports/fastwalk_dirent_ino.go b/imports/fastwalk_dirent_ino.go
index 32fe71b28b..ee85bc4dd4 100644
--- a/imports/fastwalk_dirent_ino.go
+++ b/imports/fastwalk_dirent_ino.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build linux darwin
+// +build linux,!appengine darwin
 
 package imports
 
diff --git a/imports/fastwalk_portable.go b/imports/fastwalk_portable.go
index 996c2c29b7..6c2658347d 100644
--- a/imports/fastwalk_portable.go
+++ b/imports/fastwalk_portable.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !linux,!darwin,!freebsd,!openbsd,!netbsd
+// +build appengine !linux,!darwin,!freebsd,!openbsd,!netbsd
 
 package imports
 
diff --git a/imports/fastwalk_unix.go b/imports/fastwalk_unix.go
index 2449523a6a..5854233db9 100644
--- a/imports/fastwalk_unix.go
+++ b/imports/fastwalk_unix.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build linux darwin freebsd openbsd netbsd
+// +build linux,!appengine darwin freebsd openbsd netbsd
 
 package imports