Fix missing tlibc include directory for sys crates

Previously the sys crates were using the vendored headers, but not the
vendored `tlibc` directory. This would result in errors relating to
`time.h` when building the sys crates on some platforms. Now the
vendored `tlibc` is included when building the sys crates.

.github/workflows/ci.yaml

@@ -198,7 +198,7 @@ jobs:
         with:
           files: lcov.info
 
-  # This job ensures that the specified crates are able to build without alloc.  By proxy this also ensures that the
+  # This job ensures that the specified crates are able to build without alloc.  By proxy this also ensures that they
   # build with no_std
   build-no-alloc:
     runs-on: ubuntu-22.04
@@ -212,6 +212,7 @@ jobs:
           - thumbv8m.main-none-eabi
           - aarch64-linux-android
           - aarch64-apple-ios
+          - wasm32-unknown-unknown
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@master
@@ -220,17 +221,14 @@ jobs:
           targets: ${{ matrix.target }},x86_64-unknown-linux-gnu
           components: rust-src
       - uses: r7kamura/rust-problem-matchers@v1
-      - name: Build types with no alloc crate on various platfroms
-        # Some notes on this build command:
-        # - The vendored headers are used to get the necessary DCAP headers
-        # - The vendored `tlibc` is used to get a compilable `time.h` for the target.
-        # - In the unlikely event that the target was installed with rustup, this would error out with
-        #   duplicate core symbols due to `-Z build-std=core`.
+      - name: Build types with no alloc crate on various platforms
+        # In the unlikely event that the target was installed with rustup, this would error out with duplicate core
+        # symbols due to `-Z build-std=core`.
         run: |
           cargo metadata --no-deps --format-version=1 |  \
             jq -r '.packages[].name' | \
             grep -e types | \
-            xargs -n1 sh -c 'CFLAGS="-isystem${GITHUB_WORKSPACE}/core/build/headers -isystem${GITHUB_WORKSPACE}/core/build/headers/tlibc" cargo +nightly-2022-12-13 build -Z build-std=core --target ${{ matrix.target }} -p $0 --locked || exit 255'
+            xargs -n1 sh -c 'cargo +nightly-2022-12-13 build -Z build-std=core --target ${{ matrix.target }} -p $0 --locked || exit 255'
 
   notify:
     runs-on: ubuntu-latest

core/build/src/lib.rs

@@ -64,9 +64,7 @@ pub fn normalize_item_name(name: &str) -> Option<String> {
 /// Returns a builder configured with the defaults for using bindgen with the
 /// SGX libraries.
 pub fn sgx_builder() -> Builder {
-    let include_path = sgx_include_string();
-
-    let builder = Builder::default()
+    let mut builder = Builder::default()
         .derive_copy(false)
         .derive_debug(false)
         .default_enum_style(EnumVariation::NewType {
@@ -77,10 +75,13 @@ pub fn sgx_builder() -> Builder {
         .use_core()
         .ctypes_prefix("core::ffi")
         .allowlist_recursively(false)
-        .clang_args(env_c_flags())
-        .clang_arg(format!("-I{include_path}"));
+        .clang_args(env_c_flags());
 
-    cargo_emit::rerun_if_changed!(include_path);
+    for include_path in vendored_include_paths() {
+        let include_path = include_path.display();
+        builder = builder.clang_arg(format!("-I{include_path}"));
+        cargo_emit::rerun_if_changed!(include_path);
+    }
 
     builder
 }
@@ -268,22 +269,12 @@ fn sgx_sdk_dir() -> Option<PathBuf> {
 /// scattered about the repo.
 const CARGO_MANIFEST_DIR: &str = env!("CARGO_MANIFEST_DIR");
 
-/// Return the SGX include path
+/// Return the SGX include paths
 ///
-/// Will first attempt to look at the environment variable `SGX_SDK`, if that
-/// isn't present then the "headers" directory of this crate will be used.
-pub fn sgx_include_dir() -> PathBuf {
-    PathBuf::from(CARGO_MANIFEST_DIR).join("headers")
-}
-
-/// Return the SGX include path as a string.
-///
-/// Calls sgx_include_dir() and converts to a string.
-pub fn sgx_include_string() -> String {
-    sgx_include_dir()
-        .to_str()
-        .expect("SGX_SDK contained invalid UTF-8 that wasn't caught by rust")
-        .to_owned()
+/// The paths to the vendored headers are always used.
+fn vendored_include_paths() -> Vec<PathBuf> {
+    let headers = PathBuf::from(CARGO_MANIFEST_DIR).join("headers");
+    vec![headers.join("tlibc"), headers]
 }
 
 /// Return the SGX library path.