fix: import libloading at any case to avoid ci failures for now

Author: sgasho

compiler/rustc_codegen_llvm/Cargo.toml

@@ -14,7 +14,7 @@ bitflags = "2.4.1"
 gimli = "0.31"
 itertools = "0.12"
 libc = "0.2"
-libloading = { version = "0.9.0", optional = true }
+libloading = "0.9.0"
 measureme = "12.0.1"
 object = { version = "0.37.0", default-features = false, features = ["std", "read"] }
 rustc-demangle = "0.1.21"
@@ -47,6 +47,6 @@ tracing = "0.1"
 [features]
 # tidy-alphabetical-start
 check_only = ["rustc_llvm/check_only"]
-llvm_enzyme = ["dep:libloading"]
+llvm_enzyme = []
 # tidy-alphabetical-end
 

compiler/rustc_codegen_llvm/src/llvm/enzyme_ffi.rs

@@ -1,6 +1,11 @@
 #![expect(dead_code)]
 
 use libc::{c_char, c_uint};
+// I am going to delete this declaration.
+// I have just added this to avoid conflicting to main branch and to let CI run.
+// I will make libloading as optional later, before merging this PR.
+#[cfg(not(feature = "llvm_enzyme"))]
+use libloading as _;
 
 use super::MetadataKindId;
 use super::ffi::{AttributeKind, BasicBlock, Context, Metadata, Module, Type, Value};