After doing: grep -r readenv *

Remember its probably going to be one of the same lines. But yours will have read_env

pam.d/login:# parsing /etc/environment needs "readenv=1"\npam.d/login:session       required   pam_env.so readenv=1\npam.d/login:session       required   pam_env.so readenv=1 envfile=/etc/default/locale\npam.d/su:# parsing /etc/environment needs "readenv=1"\npam.d/su:session       required   pam_env.so readenv=1\npam.d/su:session       required   pam_env.so readenv=1 envfile=/etc/default/locale\npam.d/gdm:auth    required        pam_env.so readenv=1\npam.d/gdm:auth    required        pam_env.so readenv=1 envfile=/etc/default/locale\npam.d/gdm-autologin:auth    required        pam_env.so readenv=1\npam.d/gdm-autologin:auth    required        pam_env.so readenv=1 envfile=/etc/default/locale