[patch, ARM] Fix PR target/49816

[Richard Earnshaw]

In C it makes no difference if a function returning a pointer returns
false or NULL, but in when bootstrapping in C++ it's another story.

Fixed thusly:

2011-07-23  Richard Earnshaw  <rearn...@arm.com>

        PR target/49816
        * arm.c (aapcs_vfp_allocate_return_reg): Return NULL on failure.

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 6e2b799..a51c87a 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3996,7 +3996,7 @@ aapcs_vfp_allocate_return_reg (enum arm_pcs pcs_variant ATTRIBUTE_UNUSED,
 			       const_tree type ATTRIBUTE_UNUSED)
 {
   if (!use_vfp_abi (pcs_variant, false))
-    return false;
+    return NULL;
 
   if (mode == BLKmode || (mode == TImode && !TARGET_NEON))
     {