I tried compiling manually and I don't see anything weird but it keeps linking to the same libraries. I added -lpthread but that didn't make a difference.
$ make LUAROCKS=1 CFLAGS="-O2 -fPIC -lpthread -I/home/me/sandbox/include" LIBFLAG="-shared" LUA=/home/me/sandbox/bin/lua LUAC=/home/me/sandbox/bin/luac
/home/me/sandbox/bin/lua ../tools/bin2c.lua keeper.lua -o keeper.lch
cc -O2 -fPIC -lpthread -I/home/me/sandbox/include -c -o lanes.o lanes.c
cc -O2 -fPIC -lpthread -I/home/me/sandbox/include -c -o threading.o threading.c
cc -O2 -fPIC -lpthread -I/home/me/sandbox/include -c -o tools.o tools.c
cc -O2 -fPIC -lpthread -I/home/me/sandbox/include -c -o keeper.o keeper.c
cc -shared -lpthread lanes.o threading.o tools.o keeper.o -o lua51-lanes.so
$ ldd lua51-lanes.so
linux-gate.so.1 => (0xb78d2000)
libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xb7729000)
/lib/ld-linux.so.2 (0xb78d3000)
