Method mark_entry_global

crates/asm-to-binary/src/assembler/output.rs:1007–1013

Mark `entry_symbol` as a global export if it is present in the symbol table but not yet in `global_symbols`. This ensures the ELF symtab advertises the kernel entry so debuggers and QEMU can find it.

(&mut self, entry_symbol: &str)

                                .or_insert(start);
                            self.symbol_table.insert("__rodata_end".to_owned(), end);
                        }
                        SectionKind::Data => {
                            self.symbol_table
                                .entry("__data_start".to_owned())
                                .or_insert(start);
                            self.symbol_table.insert("__data_end".to_owned(), end);
                        }
                        SectionKind::Bss => {
                            self.symbol_table
                                .entry("__bss_start".to_owned())