diff --git a/Makefile b/Makefile
index 8a5a2b65f1..a341ab5d4d 100644
--- a/Makefile
+++ b/Makefile
@@ -84,9 +84,9 @@ OBJ_DIR := $(MODERN_OBJ_DIR_NAME)
 LIBPATH := -L "$(dir $(shell $(MODERNCC) -mthumb -print-file-name=libgcc.a))" -L "$(dir $(shell $(MODERNCC) -mthumb -print-file-name=libc.a))"
 endif
 
-CPPFLAGS := -iquote include -iquote $(GFLIB_SUBDIR) -Wno-trigraphs -DMODERN=$(MODERN) -nostdinc -undef
-ifeq ($(MODERN),0)
-CPPFLAGS += -I tools/agbcc/include -I tools/agbcc
+CPPFLAGS := -iquote include -iquote $(GFLIB_SUBDIR) -Wno-trigraphs -DMODERN=$(MODERN)
+ifneq ($(MODERN),1)
+CPPFLAGS += -I tools/agbcc/include -I tools/agbcc -nostdinc -undef
 endif
 
 LDFLAGS = -Map ../../$(MAP)