I know that editing GPL source code is considered as a "modification", which means all the copyleft rules apply.
However, most software includes configuration files and makefiles which you can tweak before rebuilding. Does that count as modification?
For example, I am using the swupdate
package through Yocto. I override the meta-swupdate
layer to specify specific configurations (e.g. CONFIG_LUA_PARSER=y
to enable LUA parser), and then build swupdate.