config.gcc (*-*-rtems*): Default to 'rtems' thread model.

2014-09-17  Sebastian Huber  <sebastian.huber@embedded-brains.de>

	* config.gcc (*-*-rtems*): Default to 'rtems' thread model.
	Enable selection of 'posix' or no thread model.

From-SVN: r215324

gcc/ChangeLog

+2014-09-17  Sebastian Huber  <sebastian.huber@embedded-brains.de>
+
+	* config.gcc (*-*-rtems*): Default to 'rtems' thread model.
+	Enable selection of 'posix' or no thread model.
+
 2014-09-17  Andrew Stubbs  <ams@codesourcery.com>
 
 	* config/arm/arm.c (arm_option_override): Reject -mfpu=neon

gcc/config.gcc

@@ -785,7 +785,13 @@ case ${target} in
   ;;
 *-*-rtems*)
   case ${enable_threads} in
-    yes) thread_file='rtems' ;;
+    "" | yes | rtems) thread_file='rtems' ;;
+    posix) thread_file='posix' ;;
+    no) ;;
+    *)
+      echo 'Unknown thread configuration for RTEMS'
+      exit 1
+      ;;
   esac
   tmake_file="${tmake_file} t-rtems"
   extra_options="${extra_options} rtems.opt"