Fix the exception to catch when threads is not available

.github/workflows/build.yml

@@ -0,0 +1,59 @@
+name: Build and test simple commands
+
+on: [push, pull_request]
+
+# Restrict the GITHUB_TOKEN
+permissions: {}
+
+# See build.yml
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name == 'pull_request' || github.sha }}
+  cancel-in-progress: true
+
+env:
+  res: 0
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout OCaml
+        uses: actions/checkout@v4
+        with:
+          repository: ocaml/ocaml
+          path: ocaml
+          ref: 5.3.0
+      - name: Checkout ocamlfind
+        uses: actions/checkout@v4
+        with:
+          path: ocamlfind
+          persist-credentials: false
+      - name: Configure, build and install OCaml
+        run: |
+          PREFIX="$HOME/.local"
+          echo "$PREFIX/bin" >> "$GITHUB_PATH"
+          echo "PREFIX=$PREFIX" >> "$GITHUB_ENV"
+          set -x
+          cd ocaml
+          ./configure --disable-systhreads --disable-warn-error \
+            --disable-ocamldoc --disable-ocamltest --disable-stdlib-manpages \
+            --disable-dependency-generation --prefix="$PREFIX" || res=$?
+          if ! [ "$res" = 0 ]; then cat config.log; exit "$res"; fi
+          make -j
+          make install
+      - name: Configure, build and install ocamlfind
+        run: |
+          set -x
+          cd ocamlfind
+          ./configure -bindir "$PREFIX/bin" -mandir "$PREFIX/man" \
+            -sitelib "$PREFIX/lib" -config "$PREFIX/lib/findlib.conf" \
+            -no-custom -no-camlp4
+          make all
+          make opt
+          make install
+      - name: Test ocamlfind
+        run: |
+          set -x
+          ocamlfind printconf
+          ocamlfind list
+          ocamlfind ocamlopt -config

src/findlib/frontend.ml

@@ -922,7 +922,7 @@ let ocamlc which () =
 
   let type_of_threads =
     try package_property [] "threads" "type_of_threads"
-    with Not_found -> "ignore"
+    with No_such_package _ -> "ignore"
   in
   let threads_default =
     match type_of_threads with