Unexpected behavior: file bin/hello.ml is linked in doesntwork.exe even though doesntwork.ml only depends on Hellolib.Hello whose source is lib/hello.ml.

Reproduction steps:

$ make

Output:

jbuilder runtest -f
         run alias bin/runtest
+ ./works.exe
Hello
+ ./doesntwork.exe
This shouldn't happen.
Hello

Expected output:

jbuilder runtest -f
         run alias bin/runtest
+ ./works.exe
Hello
+ ./doesntwork.exe
Hello