QUuid::createUuid does not seed the random number generator in certain situations

QUuid::createUuid does not seed the random number generator in certain cases, as the documentation says it should. This results in QUuid::createUuid creating an identical sequence of uuids from one process instance to the next.

To reproduce:

Run the attached test program several times. You can space out the program runs or seconds, minutes, or hours; it does not matter (i.e., this issue is distinct from QTBUG-8374)

Expected: A different sequence of uuids on each run.

Actual: An identical sequence of uuids.
An example run, along with the time the program was run:
$ date && ./test
Thu Jun 3 11:12:21 EDT 2010
"

{b7203c47-06bf-4878-9ff5-6afffb2db546}"
"{aae9945b-f354-4d84-bb4e-64e588a89635}"
"{3faefaa6-b843-4363-9967-f3a5e3308339}"
$ date && ./test
Thu Jun 3 11:38:50 EDT 2010
"{b7203c47-06bf-4878-9ff5-6afffb2db546}

"
"

{aae9945b-f354-4d84-bb4e-64e588a89635}"
"{3faefaa6-b843-4363-9967-f3a5e3308339}"
$ date && ./test
Thu Jun 3 14:14:09 EDT 2010
"{b7203c47-06bf-4878-9ff5-6afffb2db546}"
"{aae9945b-f354-4d84-bb4e-64e588a89635}

"
"

{3faefaa6-b843-4363-9967-f3a5e3308339}

"

More information:

• The problem will go away if the test program's call to qrand() is commented-out. Debugging into QUuid::createUuid, qsrand(), and qrand(), you will see how the call sequence in the test program results in the random number generator not being seeded.

• This is a regression. The test program behaves as expected with Qt 4.5.2.

• This appears to be an unintended consequence of commit 90a082c9, which is a fix for QTBUG-3543.

• This issue was discovered in a production application where the problematic call to qrand() was not made by application code, but by QMapData::node_create.