diff --git a/lib/emscripten/Cargo.toml b/lib/emscripten/Cargo.toml
index 4fa016d2d..3506e564f 100644
--- a/lib/emscripten/Cargo.toml
+++ b/lib/emscripten/Cargo.toml
@@ -23,8 +23,8 @@ rand = "0.6"
 [dev-dependencies]
 wabt = "0.7.2"
 
-[target.'cfg(not(windows))'.dev-dependencies]
-wasmer-llvm-backend = { path = "../llvm-backend", version = "0.1.0" }
+[target.'cfg(not(windows))'.dependencies]
+wasmer-llvm-backend = { path = "../llvm-backend", version = "0.1.0", optional = true }
 
 [build-dependencies]
 glob = "0.2.11"
diff --git a/lib/runtime-core/src/vm.rs b/lib/runtime-core/src/vm.rs
index 508ca031b..4e4d697ea 100644
--- a/lib/runtime-core/src/vm.rs
+++ b/lib/runtime-core/src/vm.rs
@@ -591,6 +591,9 @@ mod vm_ctx_tests {
 
                 namespace_table: StringTable::new(),
                 name_table: StringTable::new(),
+
+                #[cfg(feature = "vfs")]
+                custom_sections: HashMap::new(),
             },
         }
     }