StdLib: Patches and updates for ARM.

Add ARMGCC and RVCT toolchain support.
Update and Add ARM specific machine headers.
Set the empty macro for __warn_references().
Make __flt_rounds() return 'Round to nearest' by default on ARM.

Signed-off-by:  Olivier Martin [olivier.martin@arm.com]
Reviewed-by:    darylm503


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12367 6f19259b-4bc3-4df7-8a09-765794883524

StdLib/Include/Arm/machine/endian.h

@@ -0,0 +1,3 @@
+/*      $NetBSD: endian.h,v 1.3 2001/06/23 12:20:27 bjh21 Exp $ */
+
+#include <sys/endian.h>