r.terraflow: add space between literal and macro

String literal followed by define causes
'invalid suffix on literal' in clang++ [-Wreserved-user-defined-literal]
becasue C++11 requires space between literal and identifier (using -std=c++14).

The space will be just ignored when the resulting literal
is constructed.


git-svn-id: https://svn.osgeo.org/grass/grass/trunk@68817 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.terraflow/grass2str.h

@@ -141,7 +141,7 @@ cell2stream(char* cellname, elevation_type T_max_value, long* nodata_count) {
   /* close map files */
   Rast_close (infd);
 
-  G_debug(3, "nrows=%d   ncols=%d    stream_len()=%"PRI_OFF_T, nrows, ncols,
+  G_debug(3, "nrows=%d   ncols=%d    stream_len()=%" PRI_OFF_T, nrows, ncols,
 		str->stream_len());  
   assert((off_t) nrows * ncols == str->stream_len());
   rt_stop(rt);