Index: configure.in
===================================================================
--- configure.in	(revision 65)
+++ configure.in	(working copy)
@@ -31,6 +31,12 @@
 			[with_r2test=no])
 AM_CONDITIONAL([WANT_R2TEST], [test "x$with_r2test" != xno])
 
+AC_ARG_WITH([trace-stacks], [AS_HELP_STRING([--with-trace-stacks], 
+	                [enable r2's stacks debugging.])],
+	                [],
+			[with_tracestacks=no])
+AM_CONDITIONAL([WANT_OR2_TRACE_STACKS], [test "x$with_tracestacks" != xno])
+
 AC_PATH_PROGS(svnversioncommand,svnversion)
 
 if [test "x$svnversioncommand" = "x"]
Index: src/Makefile.am
===================================================================
--- src/Makefile.am	(revision 65)
+++ src/Makefile.am	(working copy)
@@ -20,6 +20,10 @@
 INCLUDES = -Iopenr2
 LIBS = -lm
 
+if WANT_OR2_TRACE_STACKS
+AM_CFLAGS := -DOR2_TRACE_STACKS
+endif
+
 if HAVE_SVNVERSION
 SVNDEF := -DREVISION=\"$(shell svnversion -n .)\"
 AM_CFLAGS := -ggdb3 -O0 -Wall -Werror $(SVNDEF)