--- configure.ac	2010-08-30 13:21:31.000000000 -0400
+++ configure.ac.new	2010-09-03 10:34:44.860929508 -0400
@@ -429,7 +429,18 @@
     ])    
     GA_UNSET_FLAGS
   fi
-  # here's where we could add a macro to look outside supplibs for shapelib
+  # look outside supplibs for shapelib
+  if test "$use_shp" != "yes" -a "$ga_dyn_supplibs" = "yes" ; then
+    echo
+    echo "Checking in system locations for libraries to support shapefiles ..."
+    AC_CHECK_HEADERS([shapefil.h], 
+    [ AC_CHECK_LIB([shp], [main],
+      [ use_shp=yes 
+        shp_inc=""
+        shp_libs="-lshp"
+      ])
+    ])
+  fi
 fi
 if test "$use_shp" != "yes" ; then
   AC_DEFINE(USESHP, 0, [Enable shapefile])