rtsfind.ads: Add RE_Lock_Read_Only into rtsfind circuitry.

rtsfind.ads: Add RE_Lock_Read_Only into rtsfind circuitry.

2011-09-27  Pascal Obry  <obry@adacore.com>

	* rtsfind.ads: Add RE_Lock_Read_Only into rtsfind circuitry.
	(RE_Id): Add RE_Lock_Read_Only.
	(RE_Unit_Table): Likewise.
	* sem_prag.adb (Process_Convention): Change Pragma_Locking_Policy
	to lift restriction on first character. Handle now the
	Name_Concurrent_Readers_Locking where policy character is set to
	'R'.
	* snames.ads-tmpl (Name_Concurrent_Readers_Locking): New
	constant.
	* exp_ch9.adb (Build_Protected_Subprogram_Body): Generate a
	read only lock for function in protected object.
	* s-taprob.ads (Lock_Read_Only): Remove obsolete comment as
	this routine is now used.

From-SVN: r179248