missing includes

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@40826 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.surf.fractal/process.c

@@ -13,6 +13,7 @@
 
 /***************************************************************************/
 
+#include <grass/raster.h>
 #include <grass/glocale.h>
 #include "frac.h"
 /* gmath.h must go last, as it can interfere with ANSI headers */