[libunwind] [libunwind] Exlcude wasm build from using __declspec export (PR #168449)

[Fangrui Song via cfe-commits]

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@@ -75,7 +75,8 @@
   #define _LIBUNWIND_EXPORT
   #define _LIBUNWIND_HIDDEN
 #else
-  #if !defined(__ELF__) && !defined(__MACH__) && !defined(_AIX)
+  #if !defined(__ELF__) && !defined(__MACH__) && !defined(_AIX) &&             \
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MaskRay wrote:

Perhaps `__has_declspec_attribute(dllexport)`  @mstorsjo 

https://github.com/llvm/llvm-project/pull/168449