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/backtrace2.c

@@ -65,7 +65,6 @@ static int PrintBacktraceUsingAddr2line(int fd, const struct StackFrame *bp) {
   char buf[kBacktraceBufSize], *argv[kBacktraceMaxFrames];
 
   if (!(debugbin = FindDebugBinary())) {
-    ShowHint("can't find .com.dbg file try setting COMDBG");
     return -1;
   }
 

libc/log/die.c

@@ -22,6 +22,7 @@
 #include "libc/log/internal.h"
 #include "libc/log/libfatal.internal.h"
 #include "libc/log/log.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/runtime.h"
 
 /**
@@ -38,8 +39,10 @@ relegated wontreturn void __die(void) {
       DebugBreak();
     }
     ShowBacktrace(2, NULL);
+    __restorewintty();
     _Exit(77);
   }
   __write_str("PANIC: __DIE() DIED\r\n");
+  __restorewintty();
   _Exit(78);
 }

libc/log/getsymboltable.c

@@ -1,35 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/calls/calls.h"
-#include "libc/runtime/runtime.h"
-#include "libc/runtime/symbols.internal.h"
-
-/**
- * Returns debug binary symbol table, as global singleton.
- * @return symbol table, or NULL w/ errno on first call
- */
-noasan struct SymbolTable *GetSymbolTable(void) {
-  static struct SymbolTable *singleton;
-  if (!singleton) {
-    ++g_ftrace;
-    singleton = OpenSymbolTable(FindDebugBinary());
-    --g_ftrace;
-  }
-  return singleton;
-}

libc/log/leaks.c

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

libc/log/oncrash.c

@@ -31,6 +31,7 @@
 #include "libc/log/log.h"
 #include "libc/macros.internal.h"
 #include "libc/nexgen32e/stackframe.h"
+#include "libc/runtime/internal.h"
 #include "libc/runtime/pc.internal.h"
 
 /**
@@ -275,7 +276,8 @@ static wontreturn relegated noinstrument void __minicrash(int sig,
           "%n",
           kind, TinyStrSignal(sig), __argv[0], ctx ? ctx->uc_mcontext.rip : 0,
           ctx ? ctx->uc_mcontext.rsp : 0, ctx ? ctx->uc_mcontext.rbp : 0);
-  quick_exit(119);
+  __restorewintty();
+  _Exit(119);
 }
 
 /**
@@ -316,6 +318,7 @@ relegated noinstrument void __oncrash(int sig, struct siginfo *si,
       if (!(gdbpid > 0 && (sig == SIGTRAP || sig == SIGQUIT))) {
         __restore_tty(1);
         ShowCrashReport(err, sig, si, ctx);
+        __restorewintty();
         _Exit(128 + sig);
       }
     } else {

libc/log/restoretty.c

@@ -22,6 +22,7 @@
 #include "libc/errno.h"
 #include "libc/log/color.internal.h"
 #include "libc/log/internal.h"
+#include "libc/runtime/internal.h"
 #include "libc/sysv/consts/termios.h"
 
 /**