Fix compilation with emscripten (#294)

* Fixes to C code for compilation with emscripten

* Added emscripten CI build

* Don't refer to non-existent all extra

* Added hashes to GA config

Author: astrofrog

.github/workflows/ci_emscripten.yml

@@ -0,0 +1,39 @@
+# GitHub Actions workflow for testing Emscripten/WebAssembly build via Pyodide
+
+name: Emscripten
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  build-wasm:
+    name: Build for WebAssembly
+    runs-on: ubuntu-22.04
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405  # v6.2.0
+        with:
+          python-version: '3.12'
+
+      - name: Install pyodide-build
+        run: pip install pyodide-build>=0.29.2
+
+      - name: Get Emscripten version
+        run: echo EMSCRIPTEN_VERSION=$(pyodide config get emscripten_version) >> $GITHUB_ENV
+
+      - name: Set up Emscripten SDK
+        uses: mymindstorm/setup-emsdk@6ab9eb1bda2574c4ddb79809fc9247783eaf9021  # v14
+        with:
+          version: ${{ env.EMSCRIPTEN_VERSION }}
+
+      - name: Build wheel for Pyodide
+        run: pyodide build

cextern/astrometry.net/qsort_reentrant.c

@@ -37,7 +37,7 @@
 #ifdef _MSC_VER
 # include <stdio.h>
 #else
-#if __sun
+#if defined(__sun) || defined(__EMSCRIPTEN__)
 # include <stdio.h>
 #else
 # include <sys/cdefs.h>

cextern/numpy/ieee754.h

@@ -70,7 +70,7 @@ static void _npy_set_floatstatus_invalid(void)
     fp_raise_xcp(FP_INVALID);
 }
 
-#elif defined(_MSC_VER) || (defined(__osf__) && defined(__alpha))
+#elif defined(_MSC_VER) || (defined(__osf__) && defined(__alpha)) || defined(__EMSCRIPTEN__)
 
 /*
  * By using a volatile floating point value,
@@ -80,6 +80,10 @@ static void _npy_set_floatstatus_invalid(void)
  * We shouldn't write multiple values to a single
  * global here, because that would cause
  * a race condition.
+ *
+ * Note: Emscripten is included here because its fenv.h implementation
+ * provides stub functions that don't actually manipulate floating-point
+ * state (WebAssembly has limited access to hardware exception mechanisms).
  */
 static volatile double _npy_floatstatus_x, _npy_floatstatus_inf;
 

tox.ini

@@ -60,7 +60,6 @@ deps =
 # The following indicates which extras_require from setup.cfg will be installed
 extras =
     test
-    alldeps: all
 
 install_command =
     !devdeps: python -I -m pip install