Fix configure-iface for make -j.

[Ralf Wildenhues]

I've applied this trivial patch to fix

| ../../libtool/tests/configure-iface.at:301: $MAKE print-ltdl
| --- /dev/null   2008-08-11 09:29:19.192040513 +0200
| +++ /home/ralf/libtool/build/tests/testsuite.dir/at-stderr 2008-08-@@ -0,0 +1 
@@
| +make[1]: warning: jobserver unavailable: using -j1.  Add `+' to parent make 
rulstdout:

Cheers,
Ralf

2008-08-11  Ralf Wildenhues  <address@hidden>

        * tests/configure-iface.at (convenience libltdl): Ignore warning
        from parallel make.

diff --git a/tests/configure-iface.at b/tests/configure-iface.at
index 9a311dc..5e33eca 100644
--- a/tests/configure-iface.at
+++ b/tests/configure-iface.at
@@ -298,7 +298,7 @@ print-ltdl:
 ]])
 
 LT_AT_BOOTSTRAP([--ltdl], [-I libltdl/m4], [ignore], [ignore], [], [], 
[ignore])
-AT_CHECK([$MAKE print-ltdl], [], [stdout])
+AT_CHECK([$MAKE print-ltdl], [], [stdout], [ignore])
 AT_CHECK([grep libltdl/libltdlc.la stdout], [], [ignore])
 
 AT_CLEANUP