I think GCC's more-or-less equivalent to Clang's --target is called -B: https://gcc.gnu.org/onlinedocs/gcc/Directory-Options.html#in...
I assume it works with an all-targets binutils build. I haven't seen anyone building their cross-compilers in this way (at least not in recent memory).
I haven't either, probably because it would require building once per target and installing all the individual binaries.
This is one of the biggest differences between clang and GCC: clang has one binary that supports multiple targets, while a GCC build is always target-specific.
Old versions of GCC used to provide `-b <machine>` (and also `-V <version>`), but they were removed a long time ago in favor of expecting people to just use and set `CC` correctly.
It looks like gcc 3.3 through 4.5 just forwards to an external driver; prior to that it seems like it used the same driver for different paths, and after that it is removed.