add m4 macros to build with dragonegg and make the memopt m4 show a message if it is active

m4/dragonegg.m4

@@ -0,0 +1,17 @@
+AC_DEFUN([AC_DRAGONEGG],
+[
+	AC_ARG_ENABLE(dragonegg,
+		AC_HELP_STRING([--enable-dragonegg],
+		               [use dragonegg llvm plugin]),
+		[use_dragonegg=$enableval],
+		[use_dragonegg=no])
+
+	if test "x$use_dragonegg" = "xyes"; then
+	  # this could be more elaborated in finding drageonegg, etc.
+		AC_MSG_NOTICE("using dragonegg gcc plugin")
+		DRAGONEGG_FLAGS="-fplugin=/usr/lib64/llvm/dragonegg.so"
+		AC_SUBST(DRAGONEGG_FLAGS)
+	fi
+])
+
+# vim: set ft=m4 ts=2 sw=2:

m4/memopt.m4

@@ -7,8 +7,9 @@ AC_DEFUN([AC_MEM_OPT],
 		[use_mem_opt=no])
 
 	if test "x$use_mem_opt" = "xyes"; then
-	MEM_OPT_FLAGS="-DMEM_OPT"
-	AC_SUBST(MEM_OPT_FLAGS)
+		AC_MSG_NOTICE("Using best fit tree based memory optimizations")
+		MEM_OPT_FLAGS="-DMEM_OPT"
+		AC_SUBST(MEM_OPT_FLAGS)
 	fi
 ])