Bug#920147: sagemath FTBFS on mipsel and mips64el

[peter green]

Package: sagemath
Version: 8.4-2
Severity: serious

sagemath versions from 8.4-2 through to 8.6-2 have failed to build on mipsel and mips64el.

mipsel is failing with

> Success: 42 tests failed, up to 90 failures are tolerated
> Error: critical test failures (e.g. timeout, segfault, etc.)
> make[2]: *** [debian/rules:238: had-few-failures] Error 1

While mips64el is failing with
> Testing that Sage starts...
> [2019-01-17 01:30:25] SageMath version 8.6, Release Date: 2019-01-15
> ------------------------------------------------------------------------
> /<<PKGBUILDDIR>>/sage/src/bin/sage: line 225:  2741 Segmentation fault      /<<PKGBUILDDIR>>/sage/src/bin/sage -c sage.all._write_started_file(); print("Yes, Sage starts.")
> Sage failed to start up.

This will need to be dealt with one way or the other (either by fixing the build failures or by requesting removal of the old binaries) before sagemath can migrate to testing.