% <userinput>scons -Q --debug=stacktrace</userinput>
scons: *** [prog.o] Source `prog.c' not found, needed by target `prog.o'.
scons: internal stack trace:
- File "bootstrap/src/engine/SCons/Job.py", line 197, in start
+ File "bootstrap/src/engine/SCons/Job.py", line 199, in start
task.prepare()
File "bootstrap/src/engine/SCons/Script/Main.py", line 167, in prepare
return SCons.Taskmaster.OutOfDateTask.prepare(self)