diff --git a/configure.ac b/configure.ac
index 76487c0c..9cdd2026 100644
--- a/configure.ac
+++ b/configure.ac
@@ -203,7 +203,7 @@ AC_DEFINE_UNQUOTED(TARGET_CPU_PLATFORM, ["$host_cpu"], [Target platform])
 
 files="broadwell cherryview haswell ivybridge sandybridge valleyview"
 for file in $files; do
-	QUICK_DUMP_EXTRA_DIST+="$file `tr '\n' ' ' < tools/quick_dump/$file`"
+	QUICK_DUMP_EXTRA_DIST="$QUICK_DUMP_EXTRA_DIST $file `tr '\n' ' ' < tools/quick_dump/$file`"
 done
 AC_SUBST(QUICK_DUMP_EXTRA_DIST)