message: fix prometheus.cmake for multi gcc env
diff: @@ -29,10 +29,13 @@ ExternalProject_Add(
  GIT_TAG ${PROMETHEUS_TAG}
  PREFIX ${PROMETHEUS_PREFIX_DIR}
  UPDATE_COMMAND ""
  - CMAKE_ARGS -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}
  + CMAKE_ARGS -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
  + -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
  + -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}
  -DBUILD_SHARED_LIBS=OFF
  -DENABLE_PUSH=OFF
  -DENABLE_COMPRESSION=OFF
  + -DENABLE_TESTING=OFF
  -DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}
  -DCMAKE_INSTALL_PREFIX:PATH=${PROMETHEUS_INSTALL_DIR}
  -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}
  