Layer 1 compatibility with previous generation or NuRan GSM product,
therefore the support for the Litecell 1.5 uses its own sources instead
of using tons of ifdef/endif.
Max's amendments:
* make headers path configurable
* use configured TRX instead of hardcoded value
* split subdir-objects into separate commit
* cosmetic changes
Change-Id: Ib1287375cb10a889625bbac8528fa60deed23a2b
Fixes: SYS#2443
Reviewed-on: https://gerrit.osmocom.org/61
Tested-by: Jenkins Builder
Reviewed-by: Harald Welte <laforge@gnumonks.org>