diff --git a/toolchain/toolchain-wrapper.mk b/toolchain/toolchain-wrapper.mk
index eba2b381e9..af39071cf3 100644
--- a/toolchain/toolchain-wrapper.mk
+++ b/toolchain/toolchain-wrapper.mk
@@ -14,7 +14,9 @@ TOOLCHAIN_WRAPPER_ARGS += -DBR_SYSROOT='"$(STAGING_SUBDIR)"'
 
 # We create a list like '"-mfoo", "-mbar", "-mbarfoo"' so that each flag is a
 # separate argument when used in execv() by the toolchain wrapper.
-TOOLCHAIN_WRAPPER_ARGS += -DBR_ADDITIONAL_CFLAGS='$(foreach f,$(call qstrip,$(BR2_TARGET_OPTIMIZATION)),"$(f)",)'
+TOOLCHAIN_WRAPPER_OPTS = \
+	$(foreach f,$(call qstrip,$(BR2_TARGET_OPTIMIZATION)),"$(f)"$(comma))
+TOOLCHAIN_WRAPPER_ARGS += -DBR_ADDITIONAL_CFLAGS='$(TOOLCHAIN_WRAPPER_OPTS)'
 
 ifeq ($(BR2_CCACHE),y)
 TOOLCHAIN_WRAPPER_ARGS += -DBR_CCACHE