Gcc 3.4-redhat sets soext to .so.1 in ada/Makefile.in. It is different from gcc 3.4 from FSF. As the result, gcc 3.4 has libgnat-3.4.so and gcc 3.4-redhat has libgnat-3.4.so.1. Ada programs compiled with gcc 3.4-redhat won't run with libgnat from gcc 3.4.
3.4-RH needs to be compatible primarily with itself.