Importing NetBSD "Kyua" test framework

To do so, a few dependencies have been imported:

 * external/bsd/lutok
 * external/mit/lua
 * external/public-domain/sqlite
 * external/public-domain/xz

The Kyua framework is the new generation of ATF (Automated Test
Framework), it is composed of:

 * external/bsd/atf
 * external/bsd/kyua-atf-compat
 * external/bsd/kyua-cli
 * external/bsd/kyua-tester
 * tests

Kyua/ATF being written in C++, it depends on libstdc++ which is
provided by GCC. As this is not part of the sources, Kyua is only
compiled when the native GCC utils are installed.

To install Kyua do the following:

 * In a cross-build enviromnent, add the following to the build.sh
   commandline: -V MKBINUTILS=yes -V MKGCCCMDS=yes

WARNING:
  At this point the import is still experimental, and not supported
  on native builds (a.k.a make build).

Change-Id: I26aee23c5bbd2d64adcb7c1beb98fe0d479d7ada

external/mit/lua/dist/test/readonly.lua

@@ -0,0 +1,12 @@
+-- make global variables readonly
+
+local f=function (t,i) error("cannot redefine global variable `"..i.."'",2) end
+local g={}
+local G=getfenv()
+setmetatable(g,{__index=G,__newindex=f})
+setfenv(1,g)
+
+-- an example
+rawset(g,"x",3)
+x=2
+y=1	-- cannot redefine `y'