Llvm_passmgr_builder

`sig type t external create : unit -> Llvm_passmgr_builder.t = "llvm_pmbuilder_create" external set_opt_level : int -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_set_opt_level" external set_size_level : int -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_set_size_level" external set_disable_unit_at_a_time : bool -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_set_disable_unit_at_a_time" external set_disable_unroll_loops : bool -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_set_disable_unroll_loops" external use_inliner_with_threshold : int -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_use_inliner_with_threshold" external populate_function_pass_manager : [ `Function ] Llvm.PassManager.t -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_populate_function_pass_manager" external populate_module_pass_manager : [ `Module ] Llvm.PassManager.t -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_populate_module_pass_manager" external populate_lto_pass_manager : [ `Module ] Llvm.PassManager.t -> internalize:bool -> run_inliner:bool -> Llvm_passmgr_builder.t -> unit = "llvm_pmbuilder_populate_lto_pass_manager" end`