cc-wrapper: autofix code style

Issue introduced in https://github.com/NixOS/nixpkgs/pull/389028

pkgs/build-support/cc-wrapper/default.nix

@@ -745,9 +745,17 @@ stdenvNoCC.mkDerivation {
     # no `/usr/include`, there’s essentially no risk to dropping
     # the flag there. See discussion in NixOS/nixpkgs#191152.
     #
-    + optionalString ((cc.isClang or false) && !(cc.isROCm or false) && !targetPlatform.isDarwin && !targetPlatform.isAndroid) ''
-      echo " -nostdlibinc" >> $out/nix-support/cc-cflags
-    ''
+    +
+      optionalString
+        (
+          (cc.isClang or false)
+          && !(cc.isROCm or false)
+          && !targetPlatform.isDarwin
+          && !targetPlatform.isAndroid
+        )
+        ''
+          echo " -nostdlibinc" >> $out/nix-support/cc-cflags
+        ''
 
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