Hello Alessandro,
That particular error message occurs when a dynamic relocation would
need to be created in the read-only part of the shared library. This
is usually indicative that some part of libobjc2 hasn't been compiled
with -fpic or contains some assembly that is making a direct reference
to a label address rather than accessing it relative to the .got.
That is precisely what happened: an asm file referencing a C symbol's absolute address.
I changed the asm file so that it references the symbol relative to the pc.
Thanks for help 
A