Xargo build cross compiler for armv5te (tier 3)

[johnthagen]

@japaric

don’t know what’s the exact procedure for that these days but I expect that you’ll need to drop the jemalloc feature and change the alloc setting in the target specification from jemalloc to alloc

See this thread for how to disable jemalloc and use system allocator instead. The API is currently nightly-only.