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/yul/src/parser/statement/function_definition.rs

@@ -215,7 +215,7 @@ impl PolkaVMWriteLLVM for FunctionDefinition {
             self.identifier.as_str(),
             function_type,
             self.result.len(),
-            Some(inkwell::module::Linkage::External),
+            Some(inkwell::module::Linkage::Internal),
             Some((self.location.line, self.location.column)),
             true,
         )?;