docs/manual: document the br2-external NAME

Update the manual with the new external.desc mandatory file.

Take the opportunity to add a section listing all mandatory files,
Config.in, external.mk and the new external.desc, instead of just
hinting about them in the external package recipes section.

Change the examples to use the NAME-suffixed variable instead of the
raw BR2_EXTERNAL variable.

Change all references to BR2_EXTERNAL elsewhere in the manual to now
use the 'br2-external tree' terminology.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Samuel Martin <s.martin49@gmail.com>
Cc: Romain Naour <romain.naour@openwide.fr>
Cc: Julien CORJON <corjon.j@ecagroup.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/manual/adding-packages-perl.txt b/docs/manual/adding-packages-perl.txt
index 63fafe6558..4f5a6a4064 100644
--- a/docs/manual/adding-packages-perl.txt
+++ b/docs/manual/adding-packages-perl.txt
@@ -47,7 +47,7 @@ built.
 Most of these data can be retrieved from https://metacpan.org/.
 So, this file and the Config.in can be generated by running
 the script +supports/scripts/scancpan Foo-Bar+ in the Buildroot directory
-(or in the +BR2_EXTERNAL+ directory).
+(or in a br2-external tree).
 This script creates a Config.in file and foo-bar.mk file for the
 requested package, and also recursively for all dependencies specified by
 CPAN. You should still manually edit the result. In particular, the