[libunwind] [libunwind] Tweak tests for musl support. (PR #85097)

[Alastair Houghton via cfe-commits]

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@@ -11,20 +11,27 @@
 
 // Basic test for float registers number are accepted.
 
-#include <dlfcn.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unwind.h>
 
+// Using __attribute__((section("main_func"))) is Linux specific, but then
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al45tair wrote:

Fair point.

https://github.com/llvm/llvm-project/pull/85097