Tweak CI setup and fix Windows #![no_std] (#37)

- Add cron job every week (to catch compiler updates)
- Replace beta with nightly
- Add `--no-default-features` for `#![no_std]` support
- Fix `#![no_std]` support for Windows

.github/workflows/main.yml

@@ -1,4 +1,11 @@
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+  schedule:
+    - cron: '5 21 * * 5'
+  workflow_dispatch:
 
 name: CI
 
@@ -9,7 +16,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        rust: [beta, stable, 1.13.0]
+        rust: [stable, nightly, 1.13.0]
         exclude:
           # https://github.com/rust-lang/rust/issues/34674
           - os: macos-latest
@@ -24,6 +31,11 @@ jobs:
       - uses: actions-rs/cargo@v1
         with:
           command: test
+          args: --no-default-features --lib
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --all-features
 
   wasi:
     name: Test WASI

src/windows.rs

@@ -12,13 +12,17 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#[cfg(feature = "std")]
 use std::ptr;
 use winapi::shared::minwindef::DWORD;
+#[cfg(feature = "std")]
 use winapi::shared::ntdef::WCHAR;
+#[cfg(feature = "std")]
 use winapi::um::winbase::{FORMAT_MESSAGE_FROM_SYSTEM, FORMAT_MESSAGE_IGNORE_INSERTS};
 
 use Errno;
 
+#[cfg(feature = "std")]
 pub fn with_description<F, T>(err: Errno, callback: F) -> T where
     F: FnOnce(Result<&str, Errno>) -> T
 {
@@ -50,6 +54,7 @@ pub fn with_description<F, T>(err: Errno, callback: F) -> T where
     }
 }
 
+#[cfg(feature = "std")]
 pub const STRERROR_NAME: &'static str = "FormatMessageW";
 
 pub fn errno() -> Errno {