diff --git a/configure b/configure
index e774e18..a8fbb6a 100755
--- a/configure
+++ b/configure
@@ -4755,7 +4755,7 @@ else
 fi
 
         EXTRA_LIBS="${EXTRA_LIBS} ${LUA_LIB}" ;
-        CFLAGS="${CFLAGS} ${LUA_INCLUDE}" ;
+        CPPFLAGS="${CPPFLAGS} ${LUA_INCLUDE}" ;
 
 $as_echo "#define USE_LUA 1" >>confdefs.h
 
@@ -5424,7 +5424,7 @@ else
 fi
 
         EXTRA_LIBS="${EXTRA_LIBS} ${LUA_LIB}" ;
-        CFLAGS="${CFLAGS} ${LUA_INCLUDE}" ;
+        CPPFLAGS="${CPPFLAGS} ${LUA_INCLUDE}" ;
 
 $as_echo "#define USE_LUA 1" >>confdefs.h
 
diff --git a/configure.ac b/configure.ac
index f3cf689..61465b0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -55,7 +55,7 @@ AC_ARG_ENABLE(liblua,[--enable-liblua/--disable-liblua],
         AX_LUA_HEADERS([],[AC_MSG_ERROR([No lua headers found. Try --disable-liblua])])
         AX_LUA_LIBS([],[AC_MSG_ERROR([No lua libs found. Try --disable-liblua])])
         [EXTRA_LIBS="${EXTRA_LIBS} ${LUA_LIB}" ; ]
-        [CFLAGS="${CFLAGS} ${LUA_INCLUDE}" ; ]
+        [CPPFLAGS="${CPPFLAGS} ${LUA_INCLUDE}" ; ]
         AC_DEFINE(USE_LUA,1,[use lua])
       ],
       [
@@ -69,7 +69,7 @@ AC_ARG_ENABLE(liblua,[--enable-liblua/--disable-liblua],
         AX_LUA_HEADERS([],[AC_MSG_ERROR([No lua headers found. Try --disable-liblua])])
         AX_LUA_LIBS([],[AC_MSG_ERROR([No lua libs found. Try --disable-liblua])])
         [EXTRA_LIBS="${EXTRA_LIBS} ${LUA_LIB}" ; ]
-        [CFLAGS="${CFLAGS} ${LUA_INCLUDE}" ; ]
+        [CPPFLAGS="${CPPFLAGS} ${LUA_INCLUDE}" ; ]
         AC_DEFINE(USE_LUA,1,[use lua])
       ],
       [