Sometimes it is necessary to patch code after it has been
fetched.
Any files mentioned in SRC_URI
whose
names end in .patch
or
.diff
are treated as patches.
The do_patch
task automatically applies
these patches.
The build system should be able to apply patches with the "-p1"
option (i.e. one directory level in the path will be stripped
off).
If your patch needs to have more directory levels stripped off,
specify the number of levels using the "striplevel" option in
the SRC_URI
entry for the patch.
Alternatively, if your patch needs to be applied in a specific
subdirectory that is not specified in the patch file, use the
"patchdir" option in the entry.