--- a/Makefile.in
+++ b/Makefile.in
@@ -3,6 +3,7 @@ srcdir=@srcdir@
 VPATH=@srcdir@
 top_srcdir=@apr_srcdir@
 top_blddir=@apr_builddir@
+top_builddir=@top_builddir@
 
 #
 # APR (Apache Portable Runtime) library Makefile.