--- a/Makefile.in
+++ b/Makefile.in
@@ -15,7 +15,7 @@
 else
 CC	 ?= $(CC_DEFAULT)
 endif
-CFLAGS	 ?= @CFLAGS@ @LIBNL3_CLI_CFLAGS@
+CFLAGS	 = @CFLAGS@ @LIBNL3_CLI_CFLAGS@
 CPPFLAGS ?= @CPPFLAGS@
 LDFLAGS  ?= @LDFLAGS@
 DEFS	 ?= @DEFS@
