diff -rupN libimagequant-2.14.0/libimagequant.c libimagequant-2.14.0-new/libimagequant.c
--- libimagequant-2.14.0/libimagequant.c	2021-01-27 17:20:26.000000000 +0100
+++ libimagequant-2.14.0-new/libimagequant.c	2021-01-28 13:34:35.583742796 +0100
@@ -1279,7 +1279,7 @@ LIQ_NONNULL static float remap_to_palett
 
 #if __GNUC__ >= 9 || __clang__
     #pragma omp parallel for if (rows*cols > 3000) \
-        schedule(static) default(none) shared(acolormap,average_color,cols,input_image,map,n,output_pixels,rows,transparent_index) reduction(+:remapping_error)
+        schedule(static) default(none) shared(acolormap,average_color,cols,input_image,map,n,output_pixels,rows,transparent_index,background) reduction(+:remapping_error)
 #else
     #pragma omp parallel for if (rows*cols > 3000) \
         schedule(static) default(none) shared(acolormap) shared(average_color) reduction(+:remapping_error)