qi_sanitize_compile_flags: emit an error when no return value is specified
qi_sanitize_compile_flags: emit an error when no return value is specified

Change-Id: I99d8a3a95b5bf98b41a721e5f97e681416950557
Reviewed-on: http://gerrit.aldebaran.lan:8080/6240
Tested-by: cgestes <ddb78fe00abb42f91254c16a0860e38eb0781789@aldebaran-robotics.com>
Reviewed-by: cgestes <ddb78fe00abb42f91254c16a0860e38eb0781789@aldebaran-robotics.com>

dmerejkowsky/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild,aldebaran/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,dmerejkowsky/qibuild