[PATCH] libgcc: Fix aarch64 build

[Andrew Pinski]

For aarch64, libgcc is built with -Werror, after the latest
-Wunused-but-set* commit (r16-2258-g0eac9cfee8cb0b21d), a new warning
showed up:
```
../../../gcc/libgcc/config/libbid/bid_binarydecimal.c: In function
‘__binary32_to_bid128’:
../../../gcc/libgcc/config/libbid/bid_binarydecimal.c:130:31: error:
variable ‘c3’ set but not used [-Werror=unused-but-set-variable=]
  130 | { unsigned long long c0,c1,c2,c3;                               \
      |                               ^~
../../../gcc/libgcc/config/libbid/bid_binarydecimal.c:146842:5: note:
in expansion of macro ‘__mul_10x256_to_256’
146842 |     __mul_10x256_to_256 (z.w[5], z.w[4], z.w[3], z.w[2],
z.w[5], z.w[4],
       |     ^~~~~~~~~~~~~~~~~~~
```

This fixes it by casting c3 to void after the last __mul_10x64 in
__mul_10x256_to_256 macro to mark it as being "used".


OK?

libgcc/config/libbid/ChangeLog:

        * bid_binarydecimal.c (__mul_10x256_to_256): Mark c3 as being
        used.

Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
 libgcc/config/libbid/bid_binarydecimal.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libgcc/config/libbid/bid_binarydecimal.c 
b/libgcc/config/libbid/bid_binarydecimal.c
index daca2ffe306..12e32b9667a 100644
--- a/libgcc/config/libbid/bid_binarydecimal.c
+++ b/libgcc/config/libbid/bid_binarydecimal.c
@@ -132,6 +132,7 @@ UINT64 CY;                                                  
    \
   __mul_10x64(p1,c1,a1,c0);                                     \
   __mul_10x64(p2,c2,a2,c1);                                     \
   __mul_10x64(p3,c3,a3,c2);                                     \
+  (void)c3;                                                    \
 }
 
 // Set up indices for low and high parts, depending on the endian-ness.
-- 
2.43.0