[newlib-cygwin] Cygwin: pty: Fix 'Bad address' error when running 'cmd.exe /c dir'

[newlib-cygwin] Cygwin: pty: Fix 'Bad address' error when running 'cmd.exe /c dir'

[Takashi Yano]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=7589034cc3151bfac8cc3d3af5e91402a78e160b

commit 7589034cc3151bfac8cc3d3af5e91402a78e160b
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Sat Oct 22 14:05:40 2022 +0900

    Cygwin: pty: Fix 'Bad address' error when running 'cmd.exe /c dir'
    
    - If the command executed is 'cmd.exe /c [...]', runpath in spawn.cc
      will be NULL. In this case, is_console_app(runpath) check causes
      access violation. This case also the command executed is obviously
      console app., therefore, treat it as console app to fix this issue.
    
      Addresses: https://github.com/msys2/msys2-runtime/issues/108

Diff:
---
 winsup/cygwin/spawn.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index 5aa52ab1e..4fc842a2b 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -215,6 +215,8 @@ handle (int fd, bool writing)
 static bool
 is_console_app (WCHAR *filename)
 {
+  if (filename == NULL)
+    return true; /* The command executed is command.com or cmd.exe. */
   HANDLE h;
   const int id_offset = 92;
   h = CreateFileW (filename, GENERIC_READ, FILE_SHARE_READ,