Fix std build

Cargo.toml

@@ -20,8 +20,8 @@ travis-ci = { repository = "rafalh/rust-fatfs" }
 [features]
 # Use Rust std library
 std = []
-# Use dynamic allocation - required for LFN support
-alloc = ["core_io/collections"]
+# Use dynamic allocation - required for LFN support. When used without std please enable core_io/collections
+alloc = []
 # Default features
 default = ["chrono", "std", "alloc"]
 

README.md

@@ -48,7 +48,7 @@ Put this in your `Cargo.toml`:
     [dependencies]
     fatfs = { version = "0.2", features = ["core_io"], default-features = false }
 
-Note: LFN support requires `alloc` feature and makes use of `alloc` crate.
+Note: LFN support requires `alloc` and `core_io/collections` features and makes use of `alloc` crate.
 You may have to provide a memory allocator implementation.
 
 For building in `no_std` mode nightly Rust version compatible with current `core_io` crate is required.

build-nostd.sh

@@ -1,4 +1,4 @@
 #!/bin/sh
 set -e
 cargo build --no-default-features --features core_io
-cargo build --no-default-features --features core_io,alloc
+cargo build --no-default-features --features core_io,alloc,core_io/collections

src/lib.rs

@@ -22,7 +22,6 @@ extern crate chrono;
 extern crate core_io;
 
 #[cfg(all(not(feature = "std"), feature = "alloc"))]
-#[macro_use]
 extern crate alloc;
 
 mod fs;
@@ -31,7 +30,7 @@ mod dir_entry;
 mod file;
 mod table;
 
-#[cfg(feature = "alloc")]
+#[cfg(all(feature = "alloc"))]
 mod utils;
 
 #[cfg(not(feature = "std"))]
@@ -54,5 +53,5 @@ pub use dir::*;
 pub use dir_entry::*;
 pub use file::*;
 
-#[cfg(feature = "alloc")]
+#[cfg(all(feature = "alloc"))]
 pub use utils::*;