[babl] babl_space_get_icc: permit passing NULL for return length

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 714391334494fdec6efbb8738700a044bef6409e
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Nov 2 16:34:58 2018 +0100

    babl_space_get_icc: permit passing NULL for return length

 babl/babl-icc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/babl/babl-icc.c b/babl/babl-icc.c
index f463e9e..1ffe415 100644
--- a/babl/babl-icc.c
+++ b/babl/babl-icc.c
@@ -626,7 +626,7 @@ const char *babl_space_get_icc (const Babl *babl, int *length)
                               "babl profile", NULL, 0,
                               &babl_noconst->space.icc_length);
   }
-  *length = babl->space.icc_length;
+  if (length) *length = babl->space.icc_length;
   return babl->space.icc_profile;
 }