fix

Author: esigo

ci/do_ci.sh

@@ -63,7 +63,7 @@ IWYU=""
 MAKE_COMMAND="make -k -j \$(nproc)"
 if [[ "${CXX}" == "/usr/bin/clang++" ]]; then
   MAKE_COMMAND="make -k CXX=include-what-you-use CXXFLAGS=\"-Xiwyu --error_always\" -j \$(nproc)"
-  IWYU="-DCMAKE_CXX_INCLUDE_WHAT_YOU_USE=iwyu"
+  IWYU="-DCMAKE_CXX_INCLUDE_WHAT_YOU_USE=\"iwyu\""
 fi
 
 echo "make command: ${MAKE_COMMAND}"