diff --git a/cad/atlc/files/patch-src_atlc.c b/cad/atlc/files/patch-src_atlc.c
new file mode 100644
index 000000000000..63bb5eb18777
--- /dev/null
+++ b/cad/atlc/files/patch-src_atlc.c
@@ -0,0 +1,11 @@
+--- src/atlc.c.orig	2020-08-27 19:12:32 UTC
++++ src/atlc.c
+@@ -68,7 +68,7 @@ struct pixels Er_in_bitmap[MAX_DIFFERENT_PERMITTIVITIE
+ 
+ double **Vij;
+ double **Er;
+-unsigned char **oddity; 
++extern unsigned char **oddity; 
+ unsigned char **cell_type; 
+ unsigned char *image_data;
+ int width=-1, height=-1;