Replace every use of DATADIR to create a filename with a call to the new function that allows overriding DATADIR with an env var at runtime.
No attention is paid to asprintf failure.
This restores make distcheck to a passing state after commit 6b58ea began checking cairo surfaces for validity and exchanged undefined behaviour we shouldn't have been dependent on for consistent test failure.
e277276b shared: Update all users of DATADIR
clients/desktop-shell.c | 14 +++++++++++---
clients/ivi-shell-user-interface.c | 30 +++++++++++++++++++++++-------
libweston/compositor-x11.c | 6 +++++-
shared/frame.c | 33 +++++++++++++++++++++++++++++----
4 files changed, 68 insertions(+), 15 deletions(-)