DOC: add some environment variables in section 2.3
Add the missing environment variable in the 2.3 section.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index bf1e4cb..02c986f 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -477,9 +477,25 @@
user "$HAPROXY_USER"
-A special variable $HAPROXY_LOCALPEER is defined at the startup of the process
-which contains the name of the local peer. (See "-L" in the management guide.)
+Some variables are defined by HAProxy, they can be used in the configuration
+file, or could be inherited by a program (See 3.7. Programs):
+* HAPROXY_LOCALPEER: defined at the startup of the process which contains the
+ name of the local peer. (See "-L" in the management guide.)
+
+* HAPROXY_CFGFILES: list of the configuration files loaded by HAProxy,
+ separated by semicolons. Can be useful in the case you specified a
+ directory.
+
+* HAPROXY_MWORKER: In master-worker mode, this variable is set to 1.
+
+* HAPROXY_CLI: configured listeners adresses of the stats socket for every
+ processes, separated by semicolons.
+
+* HAPROXY_MASTER_CLI: In master-worker mode, listeners adresses of the master
+ CLI, separated by semicolons.
+
+See also "external-check command" for other variables.
2.4. Time format
----------------
@@ -7558,6 +7574,8 @@
PATH The PATH environment variable used when executing
the command may be set using "external-check path".
+ See also "2.3. Environment variables" for other variables.
+
If the command executed and exits with a zero status then the check is
considered to have passed, otherwise the check is considered to have
failed.