Use -gstabs instead of -g. For debugging, this is better suited to c++ code and works with the GNU utils and most other debugger, too. (But unfortunately not with /valgrind/.

I have problems with a felt-file with a variable of type 'short'. fimex abborts with

change in scaling-factor for parameter: 31,2,1000 consider using float or double datatpye

What should I do?

1. While the netcdf-format allows for only 1 scaling-factor per variable, the felt-format can have a scaling-factor per 2d-slice per variable (that are level*time scaling-factors). You should change the type of the variable and its _FillValue attribute from short to float in the file felt2nc_variables.xml.
2. If you want to save disk-space, and you know that all data of the variable can be subscribed sufficently with a packed short data-array, use the cdmWriterConfig.xml as follows:

   <variable name="31,2,1000" newname="air_temperature" type="short">
     <attribute name="_FillValue" value="-32767" type="short" />
     <attribute name="scale_factor" value="0.01" type="float" />
     <attribute name="add_offset" value="273" type="double" />
   </variable>

   In this example, the temperature will be described with an accuracy of 0.01ºC and a range of -327.66ºC (I know thats below 0K) to 327.66ºC