arm64-linux compiles

modified:   conf.h
	modified:   linker.cpp
	modified:   linker.h
	modified:   p_elf_enum.h
	modified:   p_lx_elf.cpp
	modified:   p_lx_elf.h
	modified:   packmast.cpp
	modified:   stub/Makefile
	new file:   stub/arm64-linux.shlib-init.h
	new file:   stub/src/arm64-linux.shlib-init.S
	new file:   stub/tmp/arm64-linux.elf-entry.bin.dump
	new file:   stub/tmp/arm64-linux.elf-fold.map
	new file:   stub/tmp/arm64-linux.shlib-init.bin.dump

src/linker.h

@@ -160,6 +160,15 @@ protected:
                            const char *type);
 };
 
+class ElfLinkerARM64 : public ElfLinker {
+    typedef ElfLinker super;
+
+protected:
+    virtual void alignCode(unsigned len) { alignWithByte(len, 0x90); }
+    virtual void relocate1(const Relocation *, upx_byte *location, upx_uint64_t value,
+                           const char *type);
+};
+
 class ElfLinkerArmBE : public ElfLinker {
     typedef ElfLinker super;