WIP unpacking ELF shared library

modified:   Makefile
	modified:   lzma-sdk
	modified:   p_lx_elf.cpp
	modified:   p_lx_elf.h
	modified:   p_mach.cpp
	modified:   p_unix.cpp
	modified:   p_unix.h
	modified:   packer.cpp
	modified:   packer.h
	modified:   stub/arm64-linux.elf-fold.h
	modified:   stub/src/arm64-linux.elf-fold.S
	modified:   stub/tmp/arm64-linux.elf-fold.map

src/p_unix.h

@@ -50,6 +50,7 @@ public:
 
     virtual bool canPack();
     virtual int canUnpack();
+    int find_overlay_offset(MemBuffer const &buf);
 
 protected:
     // called by the generic pack()