[PATCH] c-user: Document CONFIGURE_IMFS_ENABLE_MKFIFO

[Sebastian Huber]

Close #3840.
---
 c-user/configuring_a_system.rst | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/c-user/configuring_a_system.rst b/c-user/configuring_a_system.rst
index cdb86ec..17278c0 100644
--- a/c-user/configuring_a_system.rst
+++ b/c-user/configuring_a_system.rst
@@ -2583,6 +2583,29 @@ DESCRIPTION:
     In case this configuration option is defined, then the support to remove
     nodes is disabled in the root IMFS.
 
+.. index:: CONFIGURE_IMFS_ENABLE_MKFIFO
+
+.. _CONFIGURE_IMFS_ENABLE_MKFIFO:
+
+CONFIGURE_IMFS_ENABLE_MKFIFO
+----------------------------
+
+CONSTANT:
+    ``CONFIGURE_IMFS_ENABLE_MKFIFO``
+
+DATA TYPE:
+    Boolean feature macro.
+
+RANGE:
+    Defined or undefined.
+
+DEFAULT VALUE:
+    This is not defined by default.
+
+DESCRIPTION:
+    In case this configuration option is defined, then the support to make FIFOs
+    is enabled in the root IMFS.
+
 Block Device Cache Configuration
 ================================
 
-- 
2.16.4