configure: nad2bin check no longer needed; (user custom) grids are used via PROJ

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@74179 15284696-431f-4ddb-bdfa-cd5b030d7da7

configure.in

@@ -751,13 +751,6 @@ AC_SUBST(PROJINC)
 AC_SUBST(PROJLIB)
 AC_SUBST(PROJSHARE)
 
-# nad2bin needs to be in path for installing datum gridshift files
-
-AC_PATH_PROG(NAD2BIN, nad2bin, no)
-if test "$NAD2BIN" = "no"; then
-    AC_MSG_ERROR([*** Unable to locate nad2bin (needs to be in PATH).])
-fi
-
 # Done checking PROJ
 
 # Enable regex option