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/runtime/straceinit.greg.c

@@ -18,11 +18,9 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/bits/safemacros.internal.h"
 #include "libc/calls/strace.internal.h"
-#include "libc/fmt/conv.h"
-#include "libc/intrin/kprintf.h"
 #include "libc/log/libfatal.internal.h"
 #include "libc/runtime/internal.h"
-#include "libc/str/str.h"
+#include "libc/runtime/runtime.h"
 
 /**
  * Enables plaintext system call logging  if `--strace` flag is passed.
@@ -33,5 +31,5 @@ textstartup int __strace_init(int argc, char **argv, char **envp, long *auxv) {
       __atoul(nulltoempty(__getenv(envp, "STRACE")))) {
     ++__strace;
   }
-  return argc;
+  return (__argc = argc);
 }