Include working source trees as header search directories for models
Models may need to include local headers (#include "...") that are not reachable by standard "-I" options. These headers are found by compilers near corresponding C source files. The suggested solution will not solve all such the issues, but it will help in some cases. In general case I think that one will need to manually specify such the options, in particular paths relative to working source trees to be used as header search directories.