master a43b665605: Make `nil' values of the `:position' underline property work correctly

[Po Lu]

branch: master
commit a43b6656056bab1016030668f8e579c75a33724b
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Make `nil' values of the `:position' underline property work correctly
    
    * src/xfaces.c (Finternal_set_lisp_face_attribute): Handle cases
    where the underline property `:position' is nil.
---
 src/xfaces.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/xfaces.c b/src/xfaces.c
index e148b5d398..6a279f8719 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -3165,14 +3165,15 @@ FRAME 0 means change the face on all frames, and change 
the default
           */
           valid_p = true;
 
-          while (!NILP (CAR_SAFE(list)))
+          while (!NILP (CAR_SAFE (list)))
             {
               key = CAR_SAFE (list);
               list = CDR_SAFE (list);
               val = CAR_SAFE (list);
               list = CDR_SAFE (list);
 
-              if (NILP (key) || NILP (val))
+              if (NILP (key) || (NILP (val)
+                                && !EQ (key, QCposition)))
                 {
                   valid_p = false;
                   break;