Add new kitchen sink openbsc/utils.h and libcommon/utils.c to make three so far
static functions public (so I can use them in the upcoming OAP code).
A place to put them could have been the gprs_utils.h, but all general functions
in there have a gprs_ prefix, and todo markings to move them away. All other
libcommon headers are too specific, so I opened up this kitchen sink header.
Replace the implementation of encode_big_endian() with a call to
osmo_store64be_ext(). See comments.
Apply the change in Makefiles and C files.
Neels Hofmeyr
d48f057328