diff --git a/bitbake/lib/bb/build.py b/bitbake/lib/bb/build.py
index a4deb00..5e508fe 100644
--- a/bitbake/lib/bb/build.py
+++ b/bitbake/lib/bb/build.py
@@ -771,21 +771,22 @@ def add_tasks(tasklist, d):
             task_deps['tasks'].append(task)

         flags = d.getVarFlags(task)
-        def getTask(name):
+        def getTask(name,isFlag=False):
             if not name in task_deps:
                 task_deps[name] = {}
             if name in flags:
                 deptask = d.expand(flags[name])
-                task_deps[name][task] = deptask
+                if not isFlag or deptask != "0":
+                    task_deps[name][task] = deptask
         getTask('depends')
         getTask('rdepends')
         getTask('deptask')
         getTask('rdeptask')
         getTask('recrdeptask')
         getTask('recideptask')
-        getTask('nostamp')
-        getTask('fakeroot')
-        getTask('noexec')
+        getTask('nostamp',True)
+        getTask('fakeroot',True)
+        getTask('noexec',True)
         getTask('umask')
         task_deps['parents'][task] = []
         if 'deps' in flags: