ci: force static linking with crt-static and -static flags

.gitea/workflows/build-mips.yml

@@ -52,8 +52,10 @@ jobs:
             wget -qO- https://musl.cc/mips-linux-musl-cross.tgz | tar xz -C /opt/ &&
             export PATH="/opt/mips-linux-musl-cross/bin:$PATH" &&
             export CARGO_TARGET_MIPS_UNKNOWN_LINUX_MUSL_LINKER=mips-linux-musl-gcc &&
+            export RUSTFLAGS="-C target-feature=+crt-static -C link-arg=-static" &&
             cd backend &&
-            cargo +nightly build --target mips-unknown-linux-musl --release -Z build-std=std,panic_abort
+            cargo +nightly build --target mips-unknown-linux-musl --release -Z build-std=std,panic_abort &&
+            file /project/target/mips-unknown-linux-musl/release/backend
           '
 
     - name: Rename Binary