[compiler-rt] builtins: adjust FP80 source management (PR #183871)

[Saleem Abdulrasool via llvm-commits]

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@@ -380,7 +383,6 @@ if (NOT MSVC)
   if (NOT ANDROID)
     set(i386_SOURCES
       ${i386_SOURCES}
-      ${x86_80_BIT_SOURCES}
       i386/floatdixf.S
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compnerd wrote:

I didn't reconcile the paths, merely was driving this by the specific issues. I didn't see this fail locally, but I think that we should make this similar across the two.

https://github.com/llvm/llvm-project/pull/183871