add CRASHREPORT directly to browser

add CRASHREPORT for Windows
add ^P info to report (via DUMPLOG)

new options: crash_email, crash_name, crash_urlmax
new game command: #bugreport
new config option: CRASHREPORT_EXEC_NOSTDERR
new command line option: --bidshow

deleted helper scripts:
    NetHackCrashReport.Javascript
    nhcrashreport.lua

misc:
    update CRASHREPORTURL (will need to be updated before release)
    update bitrot in winchain
    winchain for Windows
    add missing synch_wait for NetHackW --showpaths
    add PANICTRACE (and CRASHREPORT) in mdlib.c:build_opts

missing:
    packaging (Windows needs the pdb file)
    no testing with MSVC command line build

port status:
    linux: working, but glibc's backtrace doesn't show static functions
    Windows VS: working.  pdb file is large - looking into options
    MacOS: working
    msdos: not supported
    VMS: not supported
    MSVC: planned, but not attempted
    MSYS2: working, but libbacktrace not showing symbols (yet?)

src/cmd.c

@@ -2558,6 +2558,10 @@ struct ext_func_tab extcmdlist[] = {
               doattributes, IFBURIED, NULL },
     { '@',    "autopickup", "toggle the 'autopickup' option on/off",
               dotogglepickup, IFBURIED, NULL },
+#ifdef CRASHREPORT
+    { '\0',   "bugreport", "file a bug report",
+              dobugreport, GENERALCMD | NOFUZZERCMD, NULL },
+#endif
     { 'C',    "call", "name a monster, specific object, or type of object",
               docallcmd, IFBURIED, NULL },
     { 'Z',    "cast", "zap (cast) a spell",