--- a/parallel_compare.c
+++ b/parallel_compare.c
@@ -74,8 +74,8 @@
 static sint 	**accum;
 static sint 	*diag_index;
 static char 	*slopes;
-sint ktup,window,wind_gap,signif; 
-sint *zza, *zzb, *zzc, *zzd;
+extern sint ktup,window,wind_gap,signif;
+extern sint *zza, *zzb, *zzc, *zzd;
 extern Boolean percent;
 static void make_p_ptrs(sint *tptr, sint *pl, sint naseq, sint l);
 static void make_n_ptrs(sint *tptr, sint *pl, sint naseq, sint len);