If you've tried building GCC 10.2 from source and get this message:
configure: error: Building GCC requires GMP 4.2+, MPFR 3.1.0+ and MPC 0.8.0+.
Then just install the following packages...
[user]$ sudo dnf install gmp-devel mpfr-devel libmpc-devel
If you then see:
configure: error: I suspect your system does not have 32-bit development libraries (libc and headers). If you have them, rerun configure with --enable-multilib. If you do not have them, and want to build a 64-bit-only compiler, rerun configure with --disable-multilib.
[user]$ sudo dnf install glibc-devel.i686
[user]$ sudo dnf install gmp-devel mpfr-devel libmpc-devel glibc-devel.i686