[llvm] [bazel] Add llvm_zlib to system include path (PR #121374)

[Jordan Rupprecht via llvm-commits]

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@@ -101,6 +101,10 @@ cc_library(
         ],
         "//conditions:default": [],
     }),
+    includes = select({
+        ":llvm_zlib_enabled": ["."],
+        "//conditions:default": [],
+    }),
     # Clang includes zlib with angled instead of quoted includes, so we need
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rupprecht wrote:

This comment suggests angled bracket includes should already be working, so I'm not sure why an additional change is needed. Looks like @aaronmondal set this up a long time ago; do you know what's going on here?

https://github.com/llvm/llvm-project/pull/121374