Add support for symbol table in .com files

This change fixes minor bugs and adds a feature, which lets us store the
ELF symbol table, inside the ZIP directory. We use the path /zip/.symtab
which can be safely removed using a zip editing tool, to make the binary
smaller after compilation. This supplements the existing method of using
a separate .com.dbg file, which is still supported. The intent is people
don't always know that it's a good idea to download the debug file. It's
not great having someone's first experience be a crash report, that only
has numbers rather than symbols. This will help fix that!

libc/log/leaks.c

@@ -103,6 +103,7 @@ noasan void CheckForMemoryLeaks(void) {
     PrintMemoryIntervals(2, &_mmi);
     /* PrintSystemMappings(2); */
     /* PrintGarbage(); */
+    __restorewintty();
     _Exit(78);
   }
 }