[Patch ARM] Fix arm-none-eabi builds.

[Ramana Radhakrishnan]

My patch for PR19599 yesterday had a problem with arm-none-eabi builds. 
I had missed a null pointer check of decl in an AAPCS only 
configuration. Now applied as obvious.

regards
Ramana

2013-05-16  Ramana Radhakrishnan  <ramana.radhakrish...@arm.com>

        PR target/19599
        * config/arm/arm.c (arm_function_ok_for_sibcall): Add check
        for NULL decl.
Index: gcc/config/arm/arm.c
===================================================================
--- gcc/config/arm/arm.c        (revision 198971)
+++ gcc/config/arm/arm.c        (working copy)
@@ -5426,6 +5426,7 @@ arm_function_ok_for_sibcall (tree decl, 
      sibling calls.  */
   if (TARGET_AAPCS_BASED
       && arm_abi == ARM_ABI_AAPCS
+      && decl
       && DECL_WEAK (decl))
     return false;