cdbs-edit-patch creates or edits patches for use by the CDBS simple-patchsys.mk patch system. For more
information about CDBS please see the documentation under /usr/share/doc/cdbs/.
When patchname exists, cdbs-edit-patch will set up a temporary working source tree, apply all patches up
to and including patchname in lexicographic order, and spawn an interactive shell for the developer. The
developer can then edit files in this working tree. When the developer is done and exits the shell,
cdbs-edit-patch updates patchname to reflect the changes made. To abort the process from the interactive
shell, exit with a nonzero exit value.
When patchname does not exist, cdbs-edit-patch will assume that a new patch should be created. As with
the above scenario, cdbs-edit-patch will first create a temporary working source tree and apply all
patches up to the new patch in lexicographic order. When the shell is quit, cdbs-edit-patch will create
patchname.