travis: use specific debug flags

travis_custom/custom_build

@@ -13,6 +13,7 @@ else
   export CMAKE_ADDITIONAL_OPTIONS=" ${CMAKE_ADDITIONAL_OPTIONS} -DINSTALL_DOCUMENTATION=\"ON\""
 fi
 export CMAKE_ADDITIONAL_OPTIONS="${CMAKE_ADDITIONAL_OPTIONS} -DDISABLE_DEPRECATED_MACRO_WARNING=\"ON\""
+export CMAKE_ADDITIONAL_OPTIONS="${CMAKE_ADDITIONAL_OPTIONS} -DCMAKE_CXX_FLAGS_DEBUG=\"-O1\""
 export PKG_CONFIG_PATH="${PKG_CONFIG_PATH}:/opt/openrobots/lib/pkgconfig"
 export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:/opt/openrobots/lib"
 export MAKEFLAGS="-j2"