diff --git a/Makefile.in b/Makefile.in
index 9ea4b483c..88c082011 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -272,5 +272,5 @@ config.status: configure
 	./config.status --recheck
 
 makefile.dep:
-	$(CXX) -MM $(CPPFLAGS) $(CXXFLAGS) $(SRCS) > $@
+	$(CXX) -MM $(CPPFLAGS) $(SRCS) > $@
 include makefile.dep
diff --git a/configure b/configure
index 393d8ad6a..372b2b226 100755
--- a/configure
+++ b/configure
@@ -7453,7 +7453,7 @@ fi
 
 # They don't want lua
 if test "$no_lua" = "yes"; then
-  CXXFLAGS="-DNOLUA $CXXFLAGS"
+  CPPFLAGS="-DNOLUA $CPPFLAGS"
   LIBLUA_LIBS=""
   LUA_DEPENDS=""
   LUA_BUILD=""
diff --git a/configure.ac b/configure.ac
index f88b764bc..defb0bb67 100644
--- a/configure.ac
+++ b/configure.ac
@@ -537,7 +537,7 @@ AC_HELP_STRING([--without-liblua], [Compile without lua (this will exclude all o
 
 # They don't want lua
 if test "$no_lua" = "yes"; then
-  CXXFLAGS="-DNOLUA $CXXFLAGS"
+  CPPFLAGS="-DNOLUA $CPPFLAGS"
   LIBLUA_LIBS=""
   LUA_DEPENDS=""
   LUA_BUILD=""