diff --git a/configure.ac b/configure.ac
index c5c246230..85567a327 100644
--- a/configure.ac
+++ b/configure.ac
@@ -568,10 +568,12 @@ case ${with_examples} in
 
     posix)
         OPENTHREAD_EXAMPLES_POSIX=1
+        AC_DEFINE_UNQUOTED([OPENTHREAD_EXAMPLES_POSIX],[${OPENTHREAD_EXAMPLES_POSIX}],[Define to 1 if you want to use posix examples])
         ;;
 
     cc2538)
         OPENTHREAD_EXAMPLES_CC2538=1
+        AC_DEFINE_UNQUOTED([OPENTHREAD_EXAMPLES_CC2538],[${OPENTHREAD_EXAMPLES_CC2538}],[Define to 1 if you want to use cc2538 examples])
         ;;
 
 esac
@@ -584,11 +586,9 @@ AC_DEFINE_UNQUOTED([OPENTHREAD_EXAMPLES],[${OPENTHREAD_EXAMPLES}],[OpenThread ex
 
 AC_SUBST(OPENTHREAD_EXAMPLES_POSIX)
 AM_CONDITIONAL([OPENTHREAD_EXAMPLES_POSIX], [test "${OPENTHREAD_EXAMPLES}" = "posix"])
-AC_DEFINE_UNQUOTED([OPENTHREAD_EXAMPLES_POSIX],[${OPENTHREAD_EXAMPLES_POSIX}],[Define to 1 if you want to use posix examples])
 
 AC_SUBST(OPENTHREAD_EXAMPLES_CC2538)
 AM_CONDITIONAL([OPENTHREAD_EXAMPLES_CC2538], [test "${OPENTHREAD_EXAMPLES}" = "cc2538"])
-AC_DEFINE_UNQUOTED([OPENTHREAD_EXAMPLES_CC2538],[${OPENTHREAD_EXAMPLES_CC2538}],[Define to 1 if you want to use cc2538 examples])
 
 #
 # Platform Information