To build a particular working GCC, dependencies (binutils, MPC, MPFR and GMP (and sometimes ISL)) need to be within a particular range, preferrably within the same time era. Also note that old compilers will often contain unpatched security vulnerabilities.
Binutils 2.25 (released in 2016) is compatible with GCC 1.27 (released in 1988) - this is pretty amazing.
As for the other libraries, they are not needed.
All GCC versions implement simple multiprecision integer arithmetics internally, so GMP is only required by later versions of GCC for correct handling of corner cases, especially cross compilation. GCC 1.x does not use MPFR or any other software floating point library (and this can be problematic for cross-compilation).
ISL is a relatively new dependency (it's a library used for some experimental loop optimizations). Needless to say, it is not relevant for GCC 1.x. Similarly for MPC - a multiprecision complex number library.