CI: Include libc_so in the build check

Author: kateinoigakukun

.github/workflows/main.yml

@@ -91,9 +91,9 @@ jobs:
     - name: Build libc
       shell: bash
       run: |
-        make -j4 TARGET_TRIPLE=wasm32-wasi
-        make -j4 TARGET_TRIPLE=wasm32-wasip1
-        make -j4 TARGET_TRIPLE=wasm32-wasip2 WASI_SNAPSHOT=p2
+        make -j4 TARGET_TRIPLE=wasm32-wasi default libc_so
+        make -j4 TARGET_TRIPLE=wasm32-wasip1 default libc_so
+        make -j4 TARGET_TRIPLE=wasm32-wasip2 WASI_SNAPSHOT=p2 default libc_so
 
     - name: Build libc + threads
       # Only build the thread-capable wasi-libc in the latest supported Clang