constraints: add gcc, mesa ...

Change-Id: I4f2100c1c105a08d4d89d2cfed84cc1476ddcc82
Signed-off-by: Stephane Desneux <stephane.desneux@open.eurogiciel.org>
conf: fix urls

Change-Id: I56afb5de9984dca8c15caa668e98242e4c0e5da9
Signed-off-by: Stephane Desneux <stephane.desneux@open.eurogiciel.org>