Add required includes in header file

Enable to parse the header file on its own, e.g. for language servers
(clangd).

(cherry picked from commit ce5907fc40)

src/patchelf.h

@@ -1,3 +1,12 @@
+#include <map>
+#include <memory>
+#include <optional>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "elf.h"
+
 using FileContents = std::shared_ptr<std::vector<unsigned char>>;
 
 #define ElfFileParams class Elf_Ehdr, class Elf_Phdr, class Elf_Shdr, class Elf_Addr, class Elf_Off, class Elf_Dyn, class Elf_Sym, class Elf_Verneed, class Elf_Versym