Fallback in case RELDIR not defined (trunk, https://trac.osgeo.org/grass/changeset/62632)

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@62633 15284696-431f-4ddb-bdfa-cd5b030d7da7

include/defs/gis.h

@@ -64,6 +64,10 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#ifndef RELDIR
+#define RELDIR "?"
+#endif
+
 /* adj_cellhd.c */
 void G_adjust_Cell_head(struct Cell_head *, int, int);
 void G_adjust_Cell_head3(struct Cell_head *, int, int, int);