Remove unthreaded libretro Emscripten autobuild

Since the threaded RetroArch web runner is going to replace the
current unthreaded one, I don't think the unthreaded build is necessary.

.github/workflows/autobuild.yml

@@ -1067,14 +1067,8 @@ jobs:
 
   build-libretro-emscripten:
     needs: build-libretro-stage1
-    name: LR Emscripten ${{ matrix.threading }}
+    name: LR Emscripten
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - threading: threaded
-          - threading: unthreaded
     steps:
       - name: Install dependencies
         run: |
@@ -1103,13 +1097,7 @@ jobs:
 
       - name: Configure core
         run: |
-          if [ '${{ matrix.threading }}' = 'threaded' ]
+          CLICOLOR_FORCE=1 meson setup build --cross-file libretro/meson-emscripten.txt --buildtype release -Db_lto=true -Dlibretro=true -Demscripten_threaded=true
-          then
-            threaded=true
-          else
-            threaded=false
-          fi
-          CLICOLOR_FORCE=1 meson setup build --cross-file libretro/meson-emscripten.txt --buildtype release -Db_lto=true -Dlibretro=true -Demscripten_threaded=$threaded
 
       - name: Build core
         run: |
@@ -1124,20 +1112,14 @@ jobs:
           git clone https://github.com/libretro/RetroArch retroarch --depth 1 -b $(curl -s https://api.github.com/repos/libretro/RetroArch/releases/latest | jq -r '.tag_name')
           mv mkxp-z_libretro.a retroarch/libretro_emscripten.a
           cd retroarch
-          if [ '${{ matrix.threading }}' = 'threaded' ]
+          CLICOLOR_FORCE=1 emmake make -f Makefile.emscripten LIBRETRO=mkxp-z HAVE_THREADS=1 PROXY_TO_PTHREAD=1 HAVE_AL=0 HAVE_AUDIOWORKLET=1 HAVE_WASMFS=1 HAVE_EXTRA_WASMFS=1
-          then
-            flags='HAVE_THREADS=1 PROXY_TO_PTHREAD=1 HAVE_AL=0 HAVE_AUDIOWORKLET=1 HAVE_WASMFS=1 HAVE_EXTRA_WASMFS=1'
-          else
-            flags='HAVE_THREADS=0 PROXY_TO_PTHREAD=0 HAVE_AL=1 HAVE_AUDIOWORKLET=0 HAVE_WASMFS=0 HAVE_EXTRA_WASMFS=0'
-          fi
-          CLICOLOR_FORCE=1 emmake make -f Makefile.emscripten LIBRETRO=mkxp-z $flags
           mv mkxp-z_libretro.wasm ${{ runner.temp }}/dist/mkxp-z_libretro.wasm
           mv mkxp-z_libretro.js ${{ runner.temp }}/dist/mkxp-z_libretro.js
 
       - name: Upload artifact
         uses: actions/upload-artifact@v4
         with:
-          name: mkxp-z_libretro.emscripten.${{ matrix.threading }}.${{ github.event_name == 'pull_request' && format('PR{0}', github.event.number) || github.ref_name }}-${{ steps.short-sha.outputs.sha }}
+          name: mkxp-z_libretro.emscripten.${{ github.event_name == 'pull_request' && format('PR{0}', github.event.number) || github.ref_name }}-${{ steps.short-sha.outputs.sha }}
           path: ${{ runner.temp }}/dist
 
   build-libretro-ps3: