If you wish to disable all nana code you can ‘#define’ the ‘WITHOUT_NANA’ macro. This selects versions of the macros defined in ‘I.h’,‘L.h’, etc which map to ‘/* empty */’.
So if you are using nana for your development but don't wish to force your customers to use it you can add an option to your ‘configure’ script to define/undefine ‘WITHOUT_NANA’. In addition you will need to distribute copies of the nana header files with your package to get the stubs.
Note that the ‘L.h’ and ‘DL.h’ macros use the macro variable number of arguments extension provided by GNU C. If you wish your code to be portable you should use the macros ‘VL((..))’, etc rather than ‘L(..)’ to avoid problems with non GNU C preprocessors which only take a fixed number of arguments.