diff --git a/Makefile.include b/Makefile.include
index 8df7939bfe..96a3381aff 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -774,13 +774,11 @@ $(RIOTBUILD_CONFIG_HEADER_C): FORCE
 	$(Q)'$(RIOTTOOLS)/genconfigheader/genconfigheader.sh' $(CFLAGS_WITH_MACROS) \
 		| '$(LAZYSPONGE)' $(LAZYSPONGE_FLAGS) '$@'
 
-# Immediate evaluation but keep CLAGS_WITH_MACROS deferred
-_CFLAGS := $(CFLAGS)
-CFLAGS_WITH_MACROS = $(_CFLAGS)
+CFLAGS_WITH_MACROS += $(CFLAGS)
 CFLAGS_WITH_MACROS += -DRIOT_VERSION=\"$(RIOT_VERSION)\"
+# MODULE_NAME defines. Declared in 'makefiles/modules.inc.mk'
+CFLAGS_WITH_MACROS += $(EXTDEFINES)
 
-CFLAGS := $(patsubst -D%,,$(CFLAGS))
-CFLAGS := $(patsubst -U%,,$(CFLAGS))
 CFLAGS += -include '$(RIOTBUILD_CONFIG_HEADER_C)'
 
 # include mcuboot support
diff --git a/makefiles/modules.inc.mk b/makefiles/modules.inc.mk
index 7aa1e78ec6..e337750439 100644
--- a/makefiles/modules.inc.mk
+++ b/makefiles/modules.inc.mk
@@ -2,8 +2,8 @@ _ALLMODULES = $(sort $(USEMODULE) $(USEPKG))
 
 # Define MODULE_MODULE_NAME preprocessor macros for all modules.
 ED = $(addprefix MODULE_,$(_ALLMODULES))
+# EXTDEFINES will be put in CFLAGS_WITH_MACROS
 EXTDEFINES = $(addprefix -D,$(shell echo '$(ED)' | tr 'a-z-' 'A-Z_'))
-CFLAGS += $(EXTDEFINES)
 
 # filter "pseudomodules" from "real modules", but not "no_pseudomodules"
 REALMODULES += $(filter-out $(PSEUDOMODULES), $(_ALLMODULES))