RISCV relaxations (#408)

This PR enables RISC-V relaxations and changes to internal linkage for internal function and global symbols.

See also:
https://github.com/llvm/llvm-project/issues/167381#issuecomment-3513830043

Signed-off-by: xermicus <cyrill@parity.io>

crates/llvm-context/src/polkavm/context/mod.rs

@@ -134,7 +134,7 @@ impl<'ctx> Context<'ctx> {
             module
                 .get_function(import)
                 .unwrap_or_else(|| panic!("{import} import should be declared"))
-                .set_linkage(inkwell::module::Linkage::External);
+                .set_linkage(inkwell::module::Linkage::Internal);
         }
     }