Add output of N value (number of cells considered) - Backport from trunk, https://trac.osgeo.org/grass/changeset/60035

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@60107 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.covar/main.c

@@ -109,6 +109,8 @@ int main(int argc, char *argv[])
     if (count <= 1.1)
 	G_fatal_error(_("No non-null values"));
 
+    fprintf(stdout, "N = %.0f\n", count);
+
     ii = jj = 1.0;
     for (i = 0; i < nfiles; i++) {
 	if (correlation)