This is most likely caused by this GCC bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68273
Indeed, the package no longer FTBFS on mips when built against current gcc-5 (5.3.1-15), which is supposed to fix PR68273.
The new GCC version is not available on mipsel yet, so I haven't tested it there.
-- Jakub Wilk
