Fix up some more issues with Waterbox and 0 size elf data (#3590)

waterbox/waterboxhost/src/elf.rs

@@ -148,7 +148,11 @@ impl ElfLoader {
 			if prot_addr.size != 0 {
 				// TODO:  Using no_replace false here because the linker puts eh_frame_hdr in a separate segment that overlaps the other RO segment???
 				b.mmap_fixed(prot_addr, Protection::RW, false)?;
-				b.copy_from_external(&data[segment.file_range()], addr.start)?;
+
+				let src_data = &data[segment.file_range()];
+				if src_data.len() != 0 {
+					b.copy_from_external(src_data, addr.start)?;
+				}
 				b.mprotect(prot_addr, prot)?;
 			}
 		}