program creating two targets

[Werner LEMBERG]

Folks,


assume that program `bar' creates both `file1' and `file2'.  I need a
rule like this:

  foo: file1 file2
          bar

However, in a parallel build, this might call `bar' twice which is bad
(or might even fail).  On the other hand, it is important to mention
both files as prerequisites so that they are rebuilt in case one of
them is missing.

What solution do you suggest?  I haven't found a hint in the info
manual (of GNU make 3.81).


    Werner