Draft: pthread_create, RT scheduler, and address sanitizer are incompatible in Ubuntu 18.04

When we run with the RT scheduler and the address sanitizer in Ubuntu 18.04, pthread_create will hang and never create threads. This MR adds a warning such that other users are informed about this issue

cmake_targets/build_oai

@@ -445,6 +445,7 @@ function main() {
             MAKE_CMD=ninja
             shift;;
         --sanitize-address | -fsanitize=address)
+            grep -sq "Ubuntu 18.04" /etc/os-release && echo_error "Bug in OS with this option, see CmakeList.txt" 
             CMAKE_CMD="$CMAKE_CMD -DSANITIZE_ADDRESS=True"
             shift;;
         --ittiSIM)