[workaround] doxygen segfaults on kfreebsd-*, hppa

[Petr Salinger <Petr.Salinger@seznam.cz>]

Hi,

I am unable to trace that down,
but disabling multiple threads during dot run
avoids the segfault.

hppa-porters, please take a look whether similar
workaround works also for your pet architecture.
So far at least clp, soprano, schroot are affected.

Dear doxygen maintainer, please apply the workaround bellow,
until the real cause is found.

Thanks

	Petr


--- qtools/qthread_unix.cpp
+++ qtools/qthread_unix.cpp
@@ -179,6 +179,9 @@
 int QThread::idealThreadCount()
 {
     int cores = -1;
+#ifdef __FreeBSD_kernel__
+    return -1;
+#endif
 #if defined(_OS_MAC_)
     // Mac OS X
     cores = MPProcessorsScheduled();