C:\Users\andreasg>tcsh
[andreasg@panoramix ...Users/andreasg]$ gdb --args /usr/bin/XWin -multiwindow
GNU gdb (GDB) 7.6.50.20130728-cvs (cygwin-special)
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..
Reading symbols from /usr/bin/XWin...Reading symbols from /usr/lib/debug/usr/bin/XWin.exe.dbg...done
.
done.
(gdb) r
Starting program: /usr/bin/XWin -multiwindow
[New Thread 3312.0xcf4]
[New Thread 3312.0xce8]
[New Thread 3312.0x10b0]
[New Thread 3312.0x10ac]
[New Thread 3312.0x10e0]
[New Thread 3312.0x128c]
[New Thread 3312.0x1288]
[New Thread 3312.0xe60]
[New Thread 3312.0xe5c]
[Thread 3312.0x10ac exited with code 0]
[Thread 3312.0x10e0 exited with code 0]
[Thread 3312.0x128c exited with code 0]
[Thread 3312.0x1288 exited with code 0]
[Thread 3312.0xe60 exited with code 0]
[New Thread 3312.0xe4c]
[New Thread 3312.0xe58]
[New Thread 3312.0xe50]

Program received signal SIGSYS, Bad system call.
CheckForShmSyscall () at /usr/src/debug/xorg-server-1.14.2-2/Xext/shm.c:188
188         if (shmid != -1) {
(gdb) where
#0  CheckForShmSyscall () at /usr/src/debug/xorg-server-1.14.2-2/Xext/shm.c:188
#1  ShmExtensionInit () at /usr/src/debug/xorg-server-1.14.2-2/Xext/shm.c:1257
#2  0x0000000000000000 in ?? ()
(gdb)

Program received signal SIGSYS, Bad system call.
CheckForShmSyscall () at /usr/src/debug/xorg-server-1.14.2-2/Xext/xf86bigfont.c:118
118         if (shmid != -1) {
(gdb) where
#0  CheckForShmSyscall () at /usr/src/debug/xorg-server-1.14.2-2/Xext/xf86bigfont.c:118
#1  XFree86BigfontExtensionInit () at /usr/src/debug/xorg-server-1.14.2-2/Xext/xf86bigfont.c:714
#2  0x0000000000000000 in ?? ()

--------------------------------------------------------------------------------
(gdb) handle SIGSYS nostop
Signal        Stop      Print   Pass to program Description
SIGSYS        No        Yes     Yes             Bad system call
(gdb) r
Starting program: /usr/bin/XWin -multiwindow
[New Thread 6080.0x17c8]
[New Thread 6080.0x13e4]
[New Thread 6080.0x17dc]
[New Thread 6080.0x14f8]
[New Thread 6080.0x1584]
[New Thread 6080.0x17e8]
[New Thread 6080.0x17ec]
[New Thread 6080.0x1280]
[New Thread 6080.0x1198]
[Thread 6080.0x14f8 exited with code 0]
[Thread 6080.0x1584 exited with code 0]
[Thread 6080.0x17e8 exited with code 0]
[Thread 6080.0x17ec exited with code 0]
[Thread 6080.0x1280 exited with code 0]
[New Thread 6080.0x17a4]
[New Thread 6080.0xe70]
[New Thread 6080.0x143c]

Program received signal SIGSYS, Bad system call.

Program received signal SIGSYS, Bad system call.
[New Thread 6080.0x93c]
[New Thread 6080.0x7f8]
[New Thread 6080.0x177c]
[New Thread 6080.0x1fc]
[New Thread 6080.0x494]
[New Thread 6080.0x754]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 6080.0x17a4]
0x00000001004071ea in winMsgWindowProc (hwnd=<optimized out>, message=<optimized out>,
    wParam=<optimized out>, lParam=<optimized out>)
    at /usr/src/debug/xorg-server-1.14.2-2/hw/xwin/winmsgwindow.c:58
58                  PostMessage(pScreenPriv->hwndScreen, WM_GIVEUP, 0, 0);
(gdb) where
#0  0x00000001004071ea in winMsgWindowProc (hwnd=<optimized out>, message=<optimized out>,
    wParam=<optimized out>, lParam=<optimized out>)
    at /usr/src/debug/xorg-server-1.14.2-2/hw/xwin/winmsgwindow.c:58
#1  0x0000000077139bd1 in USER32!TranslateMessageEx ()
   from /cygdrive/c/Windows/system32/USER32.dll
#2  0x000000000000050c in ?? ()
#3  0x0000000000000001 in ?? ()
#4  0x0000000000000000 in ?? ()
(gdb) bt full
#0  0x00000001004071ea in winMsgWindowProc (hwnd=<optimized out>, message=<optimized out>,
    wParam=<optimized out>, lParam=<optimized out>)
    at /usr/src/debug/xorg-server-1.14.2-2/hw/xwin/winmsgwindow.c:58
        pScreen = <optimized out>
        hwnd = <optimized out>
        message = 22
        wParam = <optimized out>
        lParam = <optimized out>
#1  0x0000000077139bd1 in USER32!TranslateMessageEx ()
   from /cygdrive/c/Windows/system32/USER32.dll
No symbol table info available.
#2  0x000000000000050c in ?? ()
No symbol table info available.
#3  0x0000000000000001 in ?? ()
No symbol table info available.
#4  0x0000000000000000 in ?? ()
No symbol table info available.