diff -Nur cfitsio.orig/fpackutil.c cfitsio/fpackutil.c
--- cfitsio.orig/fpackutil.c	2009-03-18 16:31:42.000000000 +0000
+++ cfitsio/fpackutil.c	2009-03-19 22:38:15.002056931 +0000
@@ -10,6 +10,7 @@
 #include <sys/time.h>
 #include <time.h>
 #include <stdlib.h>
+#include <math.h>
 
 /* these filename buffer are used to delete temporary files */
 /* in case the program is aborted */