Test embassy-std builds in CI

Cargo.toml

@@ -9,8 +9,11 @@ members = [
     "embassy-macros",
 ]
 
+# embassy-std enables std-only features. Since Cargo resolves all features
+# for all crates in the workspace together, including it would result in
+# incompatible features enabled in embassy.
 exclude = [
-    "third_party"
+    "embassy-std"
 ]
 
 [profile.dev]

test-build.sh

@@ -3,7 +3,8 @@
 set -euxo pipefail
 
 # embassy std
-#(cd embassy; cargo build --features log,std)
+(cd embassy; cargo build --features log,std)
+(cd embassy-std; cargo build)
 
 # embassy embedded
 (cd embassy; cargo build --target thumbv7em-none-eabi)