commit 8129cbeb62ba0fa159597137dc19e97d36dcce56
Author: Ryan C. Gordon <icculus@icculus.org>
Date:   Wed Aug 2 02:41:03 2017 -0400

    Valgrind fix for XStoreColor and XStoreColors.
    
    If the "pad" field isn't set, Valgrind will report it as uninitialized
    memory accesses when the struct is copied into the Display's send buffer.
    
    In practice, this is (probably) harmless, but Valgrind is correct in
    believing it's a bug.

diff --git a/src/StColor.c b/src/StColor.c
index d5a217fb..221fae13 100644
--- a/src/StColor.c
+++ b/src/StColor.c
@@ -50,6 +50,7 @@ XStoreColor(
     citem->green = def->green;
     citem->blue = def->blue;
     citem->flags = def->flags; /* do_red, do_green, do_blue */
+    citem->pad = 0;
 
 
     UnlockDisplay(dpy);
diff --git a/src/StColors.c b/src/StColors.c
index 17a215cc..fa1814c8 100644
--- a/src/StColors.c
+++ b/src/StColors.c
@@ -53,6 +53,7 @@ XStoreColors(
 	citem.green = defs[i].green;
 	citem.blue = defs[i].blue;
 	citem.flags = defs[i].flags;
+	citem.pad = 0;
 
 	/* note that xColorItem doesn't contain all 16-bit quantities, so
 	   we can't use Data16 */