Self-compiled xorg-server 1.20.0 crashes at startup, buffer overflow

[tumtum00 <tumtum00 at protonmail dot com>]

Self-compiled xorg-server 1.20.0 crashes at startup, buffer overflow

Hello all,

after building xorg-server 1.20.0 without errors, the XWin binary crashes at startup due to a buffer overflow. XWin 1.20.0 from Cygwin repos works as expected.

Setup:
- Freshly installed Win7 x86_64 VM
- Cygwin x86_64
- Dependencies installed as described in https://x.cygwin.com/docs/cg/prog-build-prerequisites.html, plus xcb-composite-devel
- Applied the following patches to my Cygwin environment, otherwise the build would fail:
  https://github.com/cygwinports/cygport/commit/1072fd872757bd7aa97fa8daf95ed13f70f56291
  https://github.com/cygwinports/cygport/commit/c4e0f0ec5f9a5a691fd19efe2bda3cdf278baef5
- Downloaded patched xorg-server 1.20.0-2 sources as described in https://x.cygwin.com/docs/cg/prog-obtaining-source.html, "Obtaining via Cygwin setup"

Build:
  $ cygport --64 xorg-server.cygport prep
  $ cygport --64 xorg-server.cygport compile

XWin binary
  /usr/src/xorg-server-1.20.0-2.src/xorg-server-1.20.0-2.x86_64/src/xserver-cygwin-1.20.0-2/x86_64-pc-cygwin/hw/xwin/XWin
is then executed.

The `--buildtype=debug` option was added to `cygmeson` in `xorg-server.cygport` to generate the attached reports.

I'm out of ideas on how to continue debugging this. Help would be much appreciated.

Attachment: gdb-bt-full
Description: Binary data

Attachment: XWin.0.log
Description: Text document

Attachment: cygckeck.out
Description: Binary data

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