[babl] base: fix half reference conversion expecting zeroed target

[Øyvind Kolås <ok src gnome org>]

commit cc408deb86082737cf73c7d139f13a9bd56b1626
Author: Øyvind Kolås <pippin gimp org>
Date:   Sat Jan 16 11:16:22 2016 +0100

    base: fix half reference conversion expecting zeroed target
    
    As discovered in bug #760703 the reference path is currently expecting
    zeroed memory, fix by explicitly zeroing last 32bit of mantissa.

 babl/base/type-half.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/babl/base/type-half.c b/babl/base/type-half.c
index e45e34a..57b5d7d 100644
--- a/babl/base/type-half.c
+++ b/babl/base/type-half.c
@@ -283,7 +283,7 @@ static void halfp2doubles(void *target, void *source, long numel)
                 *xp++ = (xs | xe | xm); // Combine sign bit, exponent bits, and mantissa bits
             }
         }
-        xp++; // Skip over the remaining 32 bits of the mantissa
+        *xp++ = 0; // Skip over and zero the remaining 32 bits of the mantissa
     }
 }