[Apologies for not replying to comments on this bug sooner; for some reason I'm not getting emails about it.]
I have tested "valgrind inkscape" with the *original* suppressions I supplied, and they work fine with inkscape 0.91/valgrind 3.11.0: inkscape starts up and runs. If I run without the suppressions I get lots of errors as before. I wonder whether David's problem really was a stack overflow as suggested by valgrind? I didn't look at memory consumption, but I have quite a lot and a reasonably fast machine, and inkscape took over a minute to start. Hence, I still suggest these suppressions be added to the libgc package!
