crypto/sha/keccak1600-s390x.S: Assembler messages:
  crypto/sha/keccak1600-s390x.S:399: Error: Unrecognized opcode: `cijne'
  make[1]: *** [Makefile:9736: crypto/sha/libcrypto-lib-keccak1600-s390x.o] Error 1
 
The complete logs can be found here.
I've reverted to 300.2.3+3.2.1, which builds just fine.