Keep PIC wrappers target specific.

crates/bds-ui/tests/packaging_assets.rs

@@ -240,6 +240,8 @@ fn tagged_releases_are_built_and_packaged_with_rust_tools() {
         workflow.contains("link-arg=--sysroot=/opt/ruds-x64-sysroot"),
         "the cross-linker must resolve absolute libc linker-script paths inside the x64 sysroot"
     );
+    assert!(!workflow.contains("export CC=\""));
+    assert!(!workflow.contains("export CXX=\""));
 
     let workspace_manifest = fs::read_to_string(workspace.join("Cargo.toml")).unwrap();
     let core_manifest = fs::read_to_string(workspace.join("crates/bds-core/Cargo.toml")).unwrap();