ci: add x86_64

Author: AsakuraMizu

.github/workflows/check.yml

@@ -19,6 +19,8 @@ jobs:
             target: loongarch64-unknown-none-softfloat
           - arch: aarch64
             target: aarch64-unknown-none-softfloat
+          - arch: x86_64
+            target: x86_64-unknown-none
 
     steps:
       - uses: actions/checkout@v4

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        arch: [riscv64, loongarch64, aarch64]
+        arch: [riscv64, loongarch64, aarch64, x86_64]
     uses: ./.github/workflows/test-template.yml
     with:
       arch: ${{ matrix.arch }}