This reverts commit 21abc88.

Fixes https://github.com/rust-lang/rust/issues/76020

Quote the open upstream CL (https://github.com/rust-lang/rust/issues/76026):
I'm not sure what exact problem #72746 is supposed to fix, but it's probably incomplete as it breaks the build of 1.46.0 with llvm-libunwind enabled


diff --git a/src/libunwind/build.rs b/src/libunwind/build.rs
index 31d235cf679..d4bcd2ed4e8 100644
--- a/src/libunwind/build.rs
+++ b/src/libunwind/build.rs
@@ -116,8 +116,6 @@ mod llvm_libunwind {
             cfg.flag("-fstrict-aliasing");
             cfg.flag("-funwind-tables");
             cfg.flag("-fvisibility=hidden");
-            cfg.flag_if_supported("-fvisibility-global-new-delete-hidden");
-            cfg.define("_LIBUNWIND_DISABLE_VISIBILITY_ANNOTATIONS", None);
         }
 
         let mut unwind_sources = vec![