Test failure on mips64el architecture

[tillea]

Describe the bug
When trying to run the build time test of version 0.10.8 on mips64el there are some test failures. Please see the full build log and seek for

Start 246: test::igraph_pseudo_diameter_dijkstra
...
243/551 Test #243: test::igraph_pagerank ..............................***Failed    1.15 sec

In total there are 99% tests passed, 1 tests failed out of 551

To reproduce
Not sure whether this can be reproduced on some emulated mips64el machine.

Version information
0.10.8

[szhorvat]

This is the same issue that you reported a couple of years ago (and which I can't look up at the moment due to very bad network connection). Segments of the vector that ARPACK returns are all zeros. We put many hours into this already, and @jgmbenoit reported it to ARPACK-NG, but we could never figure out the reason.

I do not suggest spending any more time on it. I'd consider ARPACK broken on that platform. Whether that's due to ARPACK or a compiler bug, I do not know,.

[szhorvat]

Finally: #1469

[szhorvat]

Closing this in favour of #1469. Let us continue the discussion there.