CI: handling of new compilation warnings

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

cmake_targets/tools/build_helper

@@ -169,7 +169,7 @@ check_warnings() {
   #we look for 'warning:' in the compilation log file
   #this is how gcc starts a warning
   #this is not perfect, we may get false positive
-  warning_count=`grep "warning:" "$1"|wc -l`
+  warning_count=`grep "warning:" "$1" | egrep -v "jobserver unavailable|disabling jobserver mode" | wc -l`
   if [ $warning_count -gt 0 ]; then
     echo_error "WARNING: $warning_count warnings. See $1"
   fi