Change config file.

Change-Id: I86479d14fe794f1bdd61fcfe7fcca1fcdc680383
diff --git a/build.sh b/build.sh
index b8e75d6..a8fbe05 100755
--- a/build.sh
+++ b/build.sh
@@ -1,5 +1,10 @@
 #!/bin/bash
 
+if [ ! -f config ];then
+	echo "Exec init.sh in the first."
+	exit 1
+fi
+
 # static / shared
 export BUILD_LIB_TYPE=shared