Error when compiling

[vanhauser-thc]

I try to follow the example commands from the README with the supplied LUA grammar, but building polyglot fails:

$ cmake -DCMAKE_BUILD_TYPE=Release -Bbuild -G Ninja -DBUILD_TESTING=OFF -DGRAMMAR_FILE=grammars/lua/Lua.g4
...
LEXER_NAME: Lua
PARSER_NAME: Lua
-- Configuring done
-- Generating done
-- Build files have been written to: /PolyGlot/build

$ ninja -C build
ninja: Entering directory `build'
ninja: error: '../srcs/antlr/grammars/lua/Lua.g4', needed by 'srcs/antlr/generated/LuaBaseListener.cpp', missing and no known rule to make it

what am I doing wrong?