This packaging directory can be used to build one version of multiple cross gcc's:

- 6.x.y
- 7.x.y
- 8.x.y

Cross toolchains are available for all release architectures and for all
ports architectures.

The gcc-X-cross package should carry no patches for the GCC build, however
when an upload of a gcc-X-cross package is required without doing a gcc-X
upload, then

 - prepare a new gcc-N package
 - save the debdiff of the existing and the new gcc-N package as
   updates.diff
 - Apply the updates.diff in the gcc-X-cross package (search debian/rules
   for updates.diff).
