configure does not detect missing lua in 5.1

[Philipp K. J. <ja...@ie...>]

I just tried to build cvs-tip (5.1) from source and
encountered the following issue:

The only Lua packages I had installed were the lua
libraries (liblua, incl dev versions). This was 
enough to build 5.0, including the Lua terminal.

When trying to build 5.1, ./configure seemed to be
happy, but make ended with an error:

Making all in LaTeX
make[3]: Entering directory
`/home/janert/Sandbox-Gnuplot5/cvs-new/gnuplot/share/LaTeX' 
test -z "BUILD_LUA" || lua ../../term/lua/gnuplot-tikz.lua style 
/bin/bash: lua: command not found 
make[3]: *** [gnuplot-lua-tikz.sty] Error 127 
make[3]: Leaving directory
`/home/janert/Sandbox-Gnuplot5/cvs-new/gnuplot/share/LaTeX' 
make[2]: *** [all-recursive] Error 1 
make[2]: Leaving directory
`/home/janert/Sandbox-Gnuplot5/cvs-new/gnuplot/share' 
make[1]: *** all-recursive] Error 1 
make[1]: Leaving directory
`/home/janert/Sandbox-Gnuplot5/cvs-new/gnuplot' 
make: *** [all] Error 2

The relevant portions of the ./configure output are:

checking for LUA... no
checking for LUA... yes
checking lua.h usability... yes
checking lua.h presence... yes
checking for lua.h... yes

I then installed lua (the interpreter itself), and
now the build succeeds. 

Should ./configure have detected the missing lua 
interpreter?

Best,

		Ph.