diff --git a/build/scripts/build_cross_tools_gcc4 b/build/scripts/build_cross_tools_gcc4
index 15f19205b1..d565051b1d 100755
--- a/build/scripts/build_cross_tools_gcc4
+++ b/build/scripts/build_cross_tools_gcc4
@@ -44,8 +44,8 @@ arm-*)
 		--with-cpu=cortex-a8 --with-arch=armv7-a --with-fpu=vfpv3"
 
 	# TODO: Disable building with TLS support for ARM until implemented.
-	binutilsConfigureArgs+="--disable-tls"
-	gccConfigureArgs+="--disable-tls"
+	binutilsConfigureArgs="$binutilsConfigureArgs --disable-tls"
+	gccConfigureArgs="$gccConfigureArgs --disable-tls"
 	;;
 *)
 	binutilsConfigureArgs="--disable-multilib"