cross compiling on aarch64 host does not work #17244

Steps to reproduce:

# Install bionic on aarch64 host, clone Bitcoin Core, ...

$ make -j 2 -C depends HOST=riscv64-linux-gnu
$ ./configure --prefix=`pwd`/depends/riscv64-linux-gnu
$ make 
Making all in src
make[1]: Entering directory '/home/ubuntu/bitcoin-core/src'
make[2]: Entering directory '/home/ubuntu/bitcoin-core/src'
make[3]: Entering directory '/home/ubuntu/bitcoin-core'
make[3]: Leaving directory '/home/ubuntu/bitcoin-core'
  CXX      crypto/libbitcoinconsensus_la-chacha_poly_aead.lo
  CXX      crypto/libbitcoinconsensus_la-chacha20.lo
  CXX      crypto/libbitcoinconsensus_la-poly1305.lo
  CXX      crypto/libbitcoinconsensus_la-ripemd160.lo
  CXX      crypto/libbitcoinconsensus_la-sha1.lo
  CXX      crypto/libbitcoinconsensus_la-sha256.lo
  CXX      crypto/libbitcoinconsensus_la-sha512.lo
  CXX      libbitcoinconsensus_la-arith_uint256.lo
  CXX      consensus/libbitcoinconsensus_la-merkle.lo
  CXX      consensus/libbitcoinconsensus_la-tx_check.lo
  CXX      libbitcoinconsensus_la-hash.lo
  CXX      primitives/libbitcoinconsensus_la-block.lo
  CXX      primitives/libbitcoinconsensus_la-transaction.lo
  CXX      libbitcoinconsensus_la-pubkey.lo
  CXX      script/libbitcoinconsensus_la-bitcoinconsensus.lo
  CXX      script/libbitcoinconsensus_la-interpreter.lo
  CXX      script/libbitcoinconsensus_la-script.lo
  CXXLD    libbitcoinconsensus.la
/usr/lib/gcc-cross/riscv64-linux-gnu/7/../../../../riscv64-linux-gnu/bin/ld: support/.libs/libbitcoinconsensus_la-cleanse.o: Relocations in generic ELF (EM: 183)
/usr/lib/gcc-cross/riscv64-linux-gnu/7/../../../../riscv64-linux-gnu/bin/ld: support/.libs/libbitcoinconsensus_la-cleanse.o: Relocations in generic ELF (EM: 183)
/usr/lib/gcc-cross/riscv64-linux-gnu/7/../../../../riscv64-linux-gnu/bin/ld: support/.libs/libbitcoinconsensus_la-cleanse.o: Relocations in generic ELF (EM: 183)
/usr/lib/gcc-cross/riscv64-linux-gnu/7/../../../../riscv64-linux-gnu/bin/ld: support/.libs/libbitcoinconsensus_la-cleanse.o: Relocations in generic ELF (EM: 183)
/usr/lib/gcc-cross/riscv64-linux-gnu/7/../../../../riscv64-linux-gnu/bin/ld: support/.libs/libbitcoinconsensus_la-cleanse.o: Relocations in generic ELF (EM: 183)
/usr/lib/gcc-cross/riscv64-linux-gnu/7/../../../../riscv64-linux-gnu/bin/ld: support/.libs/libbitcoinconsensus_la-cleanse.o: Relocations in generic ELF (EM: 183)
support/.libs/libbitcoinconsensus_la-cleanse.o: error adding symbols: File in wrong format
collect2: error: ld returned 1 exit status
Makefile:4775: recipe for target 'libbitcoinconsensus.la' failed
make[2]: *** [libbitcoinconsensus.la] Error 1
make[2]: Leaving directory '/home/ubuntu/bitcoin-core/src'
Makefile:13476: recipe for target 'all-recursive' failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory '/home/ubuntu/bitcoin-core/src'
Makefile:778: recipe for target 'all-recursive' failed
make: *** [all-recursive] Error 1

Did you do a make clean beforehand? It looks like support/.libs/libbitcoinconsensus_la-cleanse.o isn't being built in your log (so it may be left behind from a non-cross build).