trouble with installing lighty 1.5 with lua on ubuntu

when mod_magnet wasn't yet in the 1.5, i just used

export LUA_CFLAGS="-I/usr/local/include"
export LUA_LIBS="-L/usr/local/lib -llua"

and mod_cml compiled. Now, mod_magnet is back to 1.5, but it doesn't 
compile. Nor in Ubuntu Edgy, nor in Debian testing. The 
--with-lua=lua5.1 trick doesn't work.

the lua.h is not found. Here is the error. I'm a scripter, not a gcc expert.

if /bin/bash ../libtool --tag=CC --mode=compile gcc -DHAVE_CONFIG_H 
-DLIBRARY_DIR="\"/opt/lighty/lib\"" -I. -I. -I..   -D_REENTRANT 
-D__EXTENSIONS__ -DOPENSSL_NO_KRB5  -D_FILE_OFFSET_BITS=64 
-D_LARGEFILE_SOURCE -D_LARGE_FILES -pthread -I/usr/include/glib-2.0 
-I/usr/lib/glib-2.0/include   -I/usr/local/include -g -O2 -Wall -W 
-Wshadow -pedantic -std=gnu99 -MT mod_magnet_la-mod_magnet.lo -MD -MP 
-MF ".deps/mod_magnet_la-mod_magnet.Tpo" -c -o 
mod_magnet_la-mod_magnet.lo `test -f 'mod_magnet.c' || echo 
'./'`mod_magnet.c; \
        then mv -f ".deps/mod_magnet_la-mod_magnet.Tpo" 
".deps/mod_magnet_la-mod_magnet.Plo"; else rm -f 
".deps/mod_magnet_la-mod_magnet.Tpo"; exit 1; fi
 gcc -DHAVE_CONFIG_H -DLIBRARY_DIR=\"/opt/lighty/lib\" -I. -I. -I.. 
-D_REENTRANT -D__EXTENSIONS__ -DOPENSSL_NO_KRB5 -D_FILE_OFFSET_BITS=64 
-D_LARGEFILE_SOURCE -D_LARGE_FILES -pthread -I/usr/include/glib-2.0 
-I/usr/lib/glib-2.0/include -I/usr/local/include -g -O2 -Wall -W 
-Wshadow -pedantic -std=gnu99 -MT mod_magnet_la-mod_magnet.lo -MD -MP 
-MF .deps/mod_magnet_la-mod_magnet.Tpo -c mod_magnet.c  -fPIC -DPIC -o 
.libs/mod_magnet_la-mod_magnet.o