gcc breakage?? : undefined reference to `__morestack'

[sean darcy]

F15 updated.
gcc-4.6.0-7.fc15.x86_64
gcc-c++-4.6.0-7.fc15.x86_64
libgcc-4.6.0-7.fc15.x86_64

Building kdenlive and mlt (which have built before Thursday) I'm getting

g++ -shared -Wl,-soname,libmlt++.so.3 -o libmlt++.so.0.7.3 MltConsumer.o 
MltDeque.o MltEvent.o MltFactory.o MltField.o MltFilter.o 
MltFilteredConsumer.o MltFilteredProducer.o MltFrame.o MltGeometry.o 
MltMultitrack.o MltParser.o MltPlaylist.o MltProducer.o MltProfile.o 
MltProperties.o MltPushConsumer.o MltRepository.o MltService.o 
MltTokeniser.o MltTractor.o MltTransition.o -Wl,--no-undefined 
-Wl,--as-needed -L../framework -lmlt
MltConsumer.o: In function `Mlt::Consumer::get_consumer()':
MltConsumer.cpp:(.text+0x17): undefined reference to `__morestack'
............

Isn't __morestack an internal gcc reference? It doesn't appear in the 
mlt source code.

Or is there something that needs to be fixed in the mlt code?

sean