Use AC_PATH_PROG() for leaks detection rather than AC_CHECK_TARGET_TOOLS(), as that apparently didn't do what I thought it did.
--- trunk/configure.ac 2009-11-04 00:39:30 UTC (rev 117)
+++ trunk/configure.ac 2009-11-04 09:12:26 UTC (rev 118)
@@ -115,7 +115,7 @@
AC_PROG_LIBTOOL
AC_PATH_PROGS(MIG, mig)
-AC_CHECK_TARGET_TOOLS(LEAKS, leaks)
+AC_PATH_PROG(LEAKS, leaks)
AS_IF([test "x$LEAKS" != "x"],
[AC_DEFINE(HAVE_LEAKS, 1, [Define if Apple leaks program is present])]
)