Fix docsrs build (#505)

* Add docsrs build to CI

* Put cfg flags in both RUSTFLAGS and RUSTDOCFLAGS

.github/workflows/rust.yml

@@ -69,6 +69,15 @@ jobs:
         RUSTFLAGS: '--cfg curve25519_dalek_backend="simd" -C target_feature=+avx512ifma'
       run: cargo build --target x86_64-unknown-linux-gnu
 
+  build-docs:
+    name: Build docs
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: dtolnay/rust-toolchain@nightly
+    - run: make doc
+    - run: make doc-internal
+
   cross:
     strategy:
       matrix:

Makefile

@@ -1,7 +1,12 @@
 FEATURES := serde rand_core digest
 
+export RUSTFLAGS := --cfg=curve25519_dalek_backend="simd"
+export RUSTDOCFLAGS := \
+	--cfg docsrs \
+	--html-in-header docs/assets/rustdoc-include-katex-header.html
+
 doc:
-	cargo +nightly rustdoc --features "$(FEATURES)" -- --html-in-header docs/assets/rustdoc-include-katex-header.html --cfg docsrs --cfg=curve25519_dalek_backend=\"simd\"
+	cargo +nightly rustdoc --features "$(FEATURES)"
 
 doc-internal:
-	cargo +nightly rustdoc --features "$(FEATURES)" -- --html-in-header docs/assets/rustdoc-include-katex-header.html --document-private-items --cfg docsrs --cfg=curve25519_dalek_backend=\"simd\"
+	cargo +nightly rustdoc --features "$(FEATURES)" -- --document-private-items

src/backend/vector/mod.rs

@@ -50,8 +50,5 @@ pub mod scalar_mul;
 ))]
 pub(crate) use self::avx2::constants::BASEPOINT_ODD_LOOKUP_TABLE;
 
-#[cfg(any(
-    all(target_feature = "avx512ifma", feature = "precomputed-tables"),
-    all(docsrs, target_arch = "x86_64")
-))]
+#[cfg(all(target_feature = "avx512ifma", feature = "precomputed-tables"))]
 pub(crate) use self::ifma::constants::BASEPOINT_ODD_LOOKUP_TABLE;