LibELF+LibC: Add support for relative relocations in aarch64 binaries

This commit adds R_AARCH64_RELATIVE to elf.h and uses it in
ELF::perform_relative_relocations to correctly verify the relocation
type. This is the only change needed to support relative relocations for
aarch64.

Userland/Libraries/LibC/elf.h

@@ -821,3 +821,5 @@ struct elf_args {
 #define R_X86_64_RELATIVE 8
 #define R_X86_64_TPOFF64 18
 #define R_X86_64_IRELATIVE 37
+
+#define R_AARCH64_RELATIVE 1027

Userland/Libraries/LibELF/Relocation.cpp

@@ -59,7 +59,7 @@ bool perform_relative_relocations(FlatPtr base_address)
     for (unsigned i = 0; i < relocation_count; ++i) {
         size_t offset_in_section = i * relocation_entry_size;
         auto* relocation = (ElfW(Rela)*)(relocation_section_addr + offset_in_section);
-        VERIFY(ELF64_R_TYPE(relocation->r_info) == R_X86_64_RELATIVE);
+        VERIFY(ELF64_R_TYPE(relocation->r_info) == R_X86_64_RELATIVE || ELF64_R_TYPE(relocation->r_info) == R_AARCH64_RELATIVE);
         auto* patch_address = (FlatPtr*)(base_address + relocation->r_offset);
         FlatPtr relocated_address;
         if (use_addend) {