[llvm] [CMake][OCaml] Make OCaml bindings suitable for out-of-tree install (PR #123478)

[Nikita Popov via llvm-commits]

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@@ -38,12 +38,20 @@ function(add_ocaml_library name)
   set(ocaml_inputs)
 
   set(ocaml_outputs "${bin}/${name}.cma")
+  # Always use -custom when building in-tree
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nikic wrote:

Why do we always use -custom for in-tree builds? Based on https://ocaml.org/manual/4.10/intfc.html#ss:staticlink-c-code, do I correctly understand that you need -custom if you're linking statically? Wasn't the previous BUILD_SHARED_LIBS based condition correct for that?

https://github.com/llvm/llvm-project/pull/123478