Remove wrapper flags when clang called from intel

pkgs/intel-oneapi/patch_intel.nix

@@ -147,6 +147,10 @@ stdenvNoCC.mkDerivation (finalAttrs: {
         ln -s $out/bin/icpx $out/bin/c++
         ln -s $out/bin/icx  $out/bin/cc
 
+        # Use this to detect when a compiler subprocess is called
+        # from icpx (--fsycl-host-compiler)
+        echo 'export "NIX_CC_WRAPPER_INTEL=1"' >> $out/nix-support/cc-wrapper-hook
+
         sed -i 's/.*isCxx=0/isCxx=1/' $out/bin/icpx
 
         # oneMath looks for sycl libraries in bin/../lib