[Bug 49506] New: Using LLVM's libunwind causes wine build failure

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=49506

Bug ID: 49506
           Summary: Using LLVM's libunwind causes wine build failure
           Product: Wine
           Version: 5.11
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ntdll
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 67634
  --> https://bugs.winehq.org/attachment.cgi?id=67634
Proposed fix

There are multiple different implementations of libunwind -- but when building
for Linux, wine assumes https://www.nongnu.org/libunwind/ is being used.

That is true on most Linux systems, but some use LLVM libunwind
https://github.com/llvm/llvm-project/tree/master/libunwind instead.

Since Apple uses LLVM libunwind as well, all the code needed to support this is
there already - just not triggered by the various ifdefs in signal_x86_64.c.

AFAIK there is no official #define to tell libunwind implementations apart -
but checking for an implementation detail (such as the presence of
____LIBUNWIND_CONFIG_H__) should do the right thing.