Set host for Emscripten

Co-Authored-By: Oscar Benjamin <[email protected]>

Author: agriyakhetarpal

.github/workflows/ci-emscripten.yml

@@ -110,6 +110,7 @@ jobs:
             --prefix=${{ env.WASM_LIBRARY_DIR }} \
             --with-gmp=${{ env.WASM_LIBRARY_DIR }} \
             --with-mpfr=${{ env.WASM_LIBRARY_DIR }}
+            --host=wasm32-unknown-emscripten
           emmake make -j $(nproc)
           emmake make install