lua kres-gen: add a guide to re-generating

diff --git a/daemon/lua/kres-gen.sh b/daemon/lua/kres-gen.sh
index e769583b151bf821a672d70640f874d6c03db7cd..40d501470555d0242ca59c50773a1001b4535e23 100755 (executable)
--- a/daemon/lua/kres-gen.sh
+++ b/daemon/lua/kres-gen.sh
@@ -1,5 +1,19 @@
 #!/bin/sh -e
 
+### Dev's guide
+#
+# C declarations for lua are (mostly) generated to simplify maintenance.
+# (Avoid typos, accidental mismatches, etc.)
+#
+# To regenerate the C definitions for lua:
+# - you need to have debugging symbols for knot-dns and kresd;
+#   you get those by compiling with -g; for knot-dns it might be enough
+#   to just install it with debugging symbols included (in your distro way)
+# - remove file ./kres-gen.lua and run make as usual
+# - the knot-dns libraries are found via pkg-config
+# - you also need gdb on $PATH
+
+
 printf -- "--[[ This file is generated by ./kres-gen.sh ]] ffi.cdef[[\n"
 
 ## Various types (mainly), from libknot and libkres