fix error message

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1656 42af7a65-404d-4744-a932-0658087f49c3

examples/wget/target.c

@@ -66,7 +66,7 @@
 #endif
 
 #ifndef CONFIG_EXAMPLE_WGET_DRIPADDR
-#  error "You must define "
+#  error "You must define CONFIG_EXAMPLE_WGET_DRIPADDR"
 #endif
 
 #ifndef CONFIG_EXAMPLE_WGET_NETMASK