Created attachment 3935 [details] diffoscope output that corroborates the claim. Both packages libgmp-dev and libgmp-dbg contain references to the host build system in the generated file gmp.h (host references via DEBUG_PREFIX_MAP). The references should be purged from the gmp.h files.
Created attachment 3936 [details] diffoscope output that corroborates the claim.
http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=ac2b82fedc4cedf58ef3fca64301e6748033f222