basic-install: document how to continue after SELinux check

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>

automated install/basic-install.sh

@@ -2086,8 +2086,13 @@ checkSelinux() {
     if [[ "${SELINUX_ENFORCING}" -eq 1 ]] && [[ -z "${PIHOLE_SELINUX}" ]]; then
         printf "  Pi-hole does not provide an SELinux policy as the required changes modify the security of your system.\\n"
         printf "  Please refer to https://wiki.centos.org/HowTos/SELinux if SELinux is required for your deployment.\\n"
+        printf "      This check can be skipped by setting the environment variable %bPIHOLE_SELINUX%b to %btrue%b\\n" "${COL_LIGHT_RED}" "${COL_NC}" "${COL_LIGHT_RED}" "${COL_NC}"
+        printf "      e.g: export PIHOLE_SELINUX=true\\n"
+        printf "      By setting this variable to true you acknowledge there may be issues with Pi-hole during or after the install\\n"
         printf "\\n  %bSELinux Enforcing detected, exiting installer%b\\n" "${COL_LIGHT_RED}" "${COL_NC}";
         exit 1;
+    elif [[ "${SELINUX_ENFORCING}" -eq 1 ]] && [[ -n "${PIHOLE_SELINUX}" ]]; then
+        printf "  %b %bSELinux Enforcing detected%b. PIHOLE_SELINUX env variable set - installer will continue\\n" "${INFO}" "${COL_LIGHT_RED}" "${COL_NC}"
     fi
 }