Remove extern declaration for t,b,l,r

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@33096 15284696-431f-4ddb-bdfa-cd5b030d7da7

display/d.graph/options.h

@@ -1,6 +1,5 @@
 
 extern float hsize;
 extern float vsize;
-extern double t, b, l, r;
 extern int mapunits;
 extern FILE *infile;