libtool.m4 (LD): Append -melf* option to LD on IRIX with GNU ld.

* libtool.m4 (LD): Append -melf* option to LD on IRIX with GNU ld.
* ltconfig: Handle it.
* ltcf-cxx.sh: Use with_gnu_ld passed as a shell variable instead of
auto-detecting it.

From-SVN: r63150

ltconfig

@@ -1190,7 +1190,7 @@ irix5* | irix6*)
     version_type=linux
   else
     version_type=irix
-  if
+  fi
   version_type=irix
   need_lib_prefix=no
   need_version=no