Try fix Iluvatar CI job

Author: tengqm

src/flag_gems/backends.yaml

@@ -189,6 +189,7 @@ backends:
       COREX_ROOT: /usr/local/corex
       PATH: $COREX_ROOT/bin:$PATH
       LD_LIBRARY_PATH: $COREX_ROOT/lib:$LD_LIBRARY_PATH
+      CPATH: /usr/local/cuda-10.2/include
     deps:
       - torch==2.7.1+corex.4.4.0
       - torchaudio==2.7.1+corex.4.4.0