Make wee-alloc an optional feature.

BUILD

@@ -1,5 +1,12 @@
 load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library")
 
+config_setting(
+    name = "wasm",
+    values = {
+        "platforms": "@io_bazel_rules_rust//rust/platform:wasm",
+    },
+)
+
 rust_library(
     name = "proxy_wasm",
     srcs = glob(["src/*.rs"]),
@@ -8,6 +15,8 @@ rust_library(
     deps = [
         "//bazel/cargo:hashbrown",
         "//bazel/cargo:log",
-        "//bazel/cargo:wee_alloc",
-    ],
+    ] + select({
+        ":wasm": ["//bazel/cargo:wee_alloc"],
+        "//conditions:default": [],
+    }),
 )

Cargo.toml

@@ -11,7 +11,10 @@ edition = "2018"
 [dependencies]
 hashbrown = { version = "0.8", default-features = false, features = ["ahash", "inline-more"] }
 log = "0.4"
-wee_alloc = "0.4"
+wee_alloc = { version = "0.4", optional = true }
+
+[features]
+wee-alloc = ["wee_alloc"]
 
 [dev-dependencies]
 chrono = "0.4"

src/lib.rs

@@ -16,6 +16,7 @@ pub mod hostcalls;
 pub mod traits;
 pub mod types;
 
+#[cfg(feature = "wee-alloc")]
 mod allocator;
 mod dispatcher;
 mod logger;