--- a/m4/ax_lib_expat.m4
+++ b/m4/ax_lib_expat.m4
@@ -109,7 +109,7 @@
 
     if test -n "$expat_prefix"; then
         expat_include_dir="$expat_prefix/include"
-        expat_ld_flags="-L$expat_prefix/lib"
+        expat_ld_flags="-L$libdir"
         expat_lib_flags="-lexpat"
         run_expat_test="yes"
     elif test "$expat_requested" = "yes"; then