diff -p -up gap4r4/pkg/grape/nauty22/gtools.c.orig gap4r4/pkg/grape/nauty22/gtools.c
--- gap4r4/pkg/grape/nauty22/gtools.c.orig	2009-02-21 23:30:50.000000000 -0300
+++ gap4r4/pkg/grape/nauty22/gtools.c	2009-02-21 23:30:59.000000000 -0300
@@ -820,7 +820,7 @@ writerange(FILE *f, int c, long lo, long
 void
 gt_abort(char *msg)     /* Write message and halt. */
 {
-	if (msg) fprintf(stderr,msg);
+	if (msg) fprintf(stderr,"%s",msg);
 	ABORT(">E gtools");
 }
 
diff -p -up gap4r4/pkg/grape/nauty22/listg.c.orig gap4r4/pkg/grape/nauty22/listg.c
--- gap4r4/pkg/grape/nauty22/listg.c.orig	2009-02-21 23:35:26.000000000 -0300
+++ gap4r4/pkg/grape/nauty22/listg.c	2009-02-21 23:35:57.000000000 -0300
@@ -167,10 +167,10 @@ int linelength,m,n;
 		    curlen += 2;
 		}
 		curlen += itos(i+labelorg,s);
-		fprintf(f,s);
+		fprintf(f,"%s",s);
 		fprintf(f," ");
 		curlen += 1 + itos(j+labelorg,s);
-		fprintf(f,s);
+		fprintf(f,"%s",s);
 	    }
 	}
 	fprintf(f,"\n");
diff -p -up gap4r4/pkg/grape/nauty22/testg.c.orig gap4r4/pkg/grape/nauty22/testg.c
--- gap4r4/pkg/grape/nauty22/testg.c.orig	2009-02-21 23:40:21.000000000 -0300
+++ gap4r4/pkg/grape/nauty22/testg.c	2009-02-21 23:40:47.000000000 -0300
@@ -338,7 +338,7 @@ printthesevals(FILE *f)
             if (VALTYPE(ki) == BOOLTYPE)
 	    {
                 if (!VAL(ki)) fprintf(f,"not %s",ID(ki));
-                else          fprintf(f,ID(ki));
+                else          fprintf(f,"%s",ID(ki));
 	    }
 	    else if (VALTYPE(ki) == GROUPSIZE)
 	    {
@@ -365,7 +365,7 @@ printkeyvals(FILE *f, long *val)
 	    if (VALTYPE(ki) == BOOLTYPE)
 	    {
 		if (!val[i]) fprintf(f,"not %s",ID(ki));
-		else         fprintf(f,ID(ki));
+		else         fprintf(f,"%s",ID(ki));
 	    }
 	    else if (VALTYPE(ki) == GROUPSIZE)
 	    {
diff -p -up gap4r4/pkg/grape/nauty22/showg.c.orig gap4r4/pkg/grape/nauty22/showg.c
--- gap4r4/pkg/grape/nauty22/showg.c.orig	2009-02-22 02:35:57.000000000 -0300
+++ gap4r4/pkg/grape/nauty22/showg.c	2009-02-22 02:36:55.000000000 -0300
@@ -189,7 +189,7 @@ static void
 gt_abort(msg)     /* Write message and halt. */
 char *msg;
 {
-	if (msg) fprintf(stderr,msg);
+	if (msg) fprintf(stderr,"%s",msg);
 	ABORT(">E gtools");
 }
 
@@ -923,10 +923,10 @@ int linelength,m,n;
 		    curlen += 2;
 		}
 		curlen += itos(i+labelorg,s);
-		fprintf(f,s);
+		fprintf(f,"%s",s);
 		fprintf(f," ");
 		curlen += 1 + itos(j+labelorg,s);
-		fprintf(f,s);
+		fprintf(f,"%s",s);
 	    }
 	}
 	fprintf(f,"\n");