BUILD: opentracing: display warning in case of using OT_USE_VARS at compile time

Please do not set the OT_USE_VARS configuration variable, as the source
will probably not be able to compile!  For now, this variable can only
be used for experimental purposes, and is not intended for wider use.

For further clarification, please see commit 4cb2c83f4.

Must be backported to 2.5.

diff --git a/addons/ot/Makefile b/addons/ot/Makefile
index 0cc8c6aadb3a11b35952d8749a336a9b83793569..c7b0f8db9ed78159c943e38618968cb614ff7578 100644 (file)
--- a/addons/ot/Makefile
+++ b/addons/ot/Makefile
@@ -65,6 +65,8 @@ OPTIONS_OBJS += \
        addons/ot/src/util.o
 
 ifneq ($(OT_USE_VARS),)
+$(warning Please do not set the OT_USE_VARS configuration variable, as the source will probably not be able to compile!  For now, this variable can only be used for experimental purposes, and is not intended for wider use.)
+
 OT_DEFINE     = -DUSE_OT_VARS
 OPTIONS_OBJS += \
        addons/ot/src/vars.o