Only run system tests for musl

Author: gnzlbg

ci/run.sh

@@ -9,10 +9,11 @@ set -ex
 
 TARGET=$1
 
-CMD="cargo test \
+CMD_="cargo test \
   --manifest-path=crates/libm-test/Cargo.toml --all \
-  --no-default-features \
-  --target $TARGET "
+  --no-default-features "
+
+CMD="${CMD} --target ${TARGET}"
 
 $CMD
 $CMD --release
@@ -22,8 +23,8 @@ $CMD --release --features 'stable'
 
 if [ "$TARGET" = "x86_64-unknown-linux-gnu" ]; then
     export TARGET=x86_64-unknown-linux-musl
-    
-    $CMD --features 'stable checked system_libm'
-    $CMD --release --features  'stable checked system_libm'
+
+    $CMD_ --target $TARGET --features 'stable checked system_libm'
+    $CMD_ --target $TARGET --release --features  'stable checked system_libm'
 fi
 

crates/libm-test/tests/system_libm.rs

@@ -1,6 +1,6 @@
 //! Compare the results of the `libm` implementation against the system's libm.
 #![cfg(test)]
-//#![cfg(feature = "system_libm")]
+#![cfg(feature = "system_libm")]
 
 use libm_test::WithinUlps;