Workaround dev-dependencies leaking into normal build

.travis.yml

@@ -64,17 +64,26 @@ matrix:
       script:
         - cargo build --manifest-path futures/Cargo.toml --features io-compat
 
-    # Allow build fail until #1396 is fixed.
     - name: cargo build --target=thumbv6m-none-eabi
       rust: nightly
-      env: ALLOW_FAILURES=true
       install:
         - rustup target add thumbv6m-none-eabi
       script:
+        - cargo run --manifest-path ci/remove-dev-dependencies/Cargo.toml */Cargo.toml
         - cargo build --manifest-path futures/Cargo.toml
             --target thumbv6m-none-eabi
             --no-default-features
-            --features nightly
+            --features nightly,cfg-target-has-atomic
+
+    - name: cargo build --target=thumbv7m-none-eabi
+      rust: nightly
+      install:
+        - rustup target add thumbv7m-none-eabi
+      script:
+        - cargo run --manifest-path ci/remove-dev-dependencies/Cargo.toml */Cargo.toml
+        - cargo build --manifest-path futures/Cargo.toml
+            --target thumbv7m-none-eabi
+            --no-default-features
 
     - name: cargo doc
       rust: nightly
@@ -102,10 +111,6 @@ matrix:
         - git commit -m "Add API docs for $TRAVIS_TAG"
         - git push origin master
 
-  allow_failures:
-    - rust: nightly
-      env: ALLOW_FAILURES=true
-
 script:
   - cargo test --all --all-features
   - cargo test --all --all-features --release

ci/remove-dev-dependencies/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "remove-dev-dependencies"
+version = "0.1.0"
+authors = ["Wim Looman <wim@nemo157.com>"]
+edition = "2018"
+publish = false
+
+[workspace]
+
+[dependencies]
+toml_edit = "0.1.3"

ci/remove-dev-dependencies/src/main.rs

@@ -0,0 +1,12 @@
+use std::{env, error::Error, fs};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    for file in env::args().skip(1) {
+        let content = fs::read_to_string(&file)?;
+        let mut doc: toml_edit::Document = content.parse()?;
+        doc.as_table_mut().remove("dev-dependencies");
+        fs::write(file, doc.to_string())?;
+    }
+
+    Ok(())
+}