The EXTRA_MAKE hook includes Makefile.mk, but its documentation comment
still names Makefile.inc. Correct the comment to match the existing
include. This changes no build behavior.
# SILENT_DEFINE may be used to specify other defines which will not be
# reported by "haproxy -vv".
# EXTRA is used to force building or not building some extra tools.
-# EXTRA_MAKE space-separated list of external addons using a Makefile.inc
+# EXTRA_MAKE space-separated list of external addons using a Makefile.mk
# DESTDIR is not set by default and is used for installation only.
# It might be useful to set DESTDIR if you want to install haproxy
# in a sandbox.