/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/ is in gcc-7-plugin-dev-s390x-linux-gnu 7.3.0-16ubuntu3cross1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/dbxelf.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/elfos.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/glibc-stdint.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/gnu-user.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/initfini-array.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/linux-protos.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/linux.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/linux.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/s390-builtin-types.def
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/s390-builtins.def
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/s390-opts.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/s390-protos.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/s390.h
/usr/lib/gcc-cross/s390x-linux-gnu/7/plugin/include/config/s390/s390x.h