Remove all options to cargo -Zcheck-cfg

They no longer exists: rust-lang/cargo#12845

Author: Urgau

.github/workflows/bors.yml

@@ -333,7 +333,7 @@ jobs:
       - name: Setup Rust toolchain
         run: TOOLCHAIN=nightly sh ./ci/install-rust.sh
       - name: Build with check-cfg
-        run: LIBC_CI=1 LIBC_CHECK_CFG=1 cargo build -Z unstable-options -Z check-cfg=features,names,values,output
+        run: LIBC_CI=1 LIBC_CHECK_CFG=1 cargo build -Z unstable-options -Z check-cfg
 
   # These jobs doesn't actually test anything, but they're only used to tell
   # bors the build completed, as there is no practical way to detect when a