The LUA_{LIB,INC}DIR variables point to the default Lua version
specified in ports (in this case 5.2) or by the user.
When multiple versions of Lua are installed (in this case 5.2 and 5.3),
libucl's ./configure auto-detects Lua 5.3 (or perhaps the latest version
available), which is a mismatch against those in the provided
include/library paths:
checking for a Lua interpreter with version >= 5.1... lua53 <-- detected
checking for lua53... /usr/local/bin/lua53
checking for lua53 version... 5.3
...
checking for Lua header version... 5.2 <-- Passed by LUA_INCDIR
checking if Lua header version matches 5.3... no
This change explicitly specifies the version of the Lua interpreter we
want to use, which appears to sufficienty influence the behaviour of the
./configure macros.
PR: 209887
Reported by: olgeni
MFH: 2016Q2
38a31b30c1