[Buildroot] Standardizing format for specifying license(s)

[Rahul Bedarkar <Rahul.Bedarkar@imgtec.com>]

Hi all,

In package.mk, as of now, there is no standard format for specifying 
licenses under which package is released. In some cases we comma 
separate licenses while in others space separated list. It's difficult 
to parse manifest file generated by legal-info target in such cases. One 
of requirements of parsing manifest file would be checking for license 
compatibility of dependent packages.

With that in mind, I'm proposing following initial format which allows 
ease in parsing manifest file.

* If package is licensed under multiple licenses e.g. bluez5_utils 
libraries and programs are licensed under different licenses. In such 
case, comma separate licenses e.g. BLUEZ5_UTILS_LICENSE=GPLv2+, LGPLv2.1+
   If there is clear distinction between which component is licensed 
under what license then annotate the license with libraries or programs 
or others keywords. e.g. BLUEZ5_UTILS_LICENSE=GPLv2+ (programs), 
LGPLv2.1+ (libraries)

* If package is dual licensed e.g. dbus then slash separate licenses. 
e.g. DBUS_LICENSE = AFLv2.1 / GPLv2+


There was effort to comma separate licenses 
https://git.busybox.net/buildroot/log/?qt=grep&q=comma+separate+licenses 
but just comma separating licenses in many cases is not correct from 
point of different licensing terms and parsing manifest file.

Any suggestions and thoughts are welcome.

Regards,
Rahul