RFA/RFC: Pass --cache-file=/dev/null on to subconfigures

[Charles Wilson]

Ralf Wildenhues wrote:
> * Charles Wilson wrote on Fri, Sep 25, 2009 at 04:48:56PM CEST:
>> I've seen it happen -- building gdb/insight which is part of the src
>> tree if not gcc specfically -- when a precious variable contained a
>> leading space.
> 
> This is probably one of the bugs fixed by override.m4, and the insight
> part is one that the autotools update hasn't touched.

Looks that way (gdbtk & libgui):
./gdb/gdbtk/configure:# Generated by GNU Autoconf 2.59.
./gdb/gdbtk/plugins/configure:# Generated by GNU Autoconf 2.59.
./gdb/testsuite/gdb.cell/configure:# Generated by GNU Autoconf 2.59.
./gdb/testsuite/gdb.gdbtk/configure:# Generated by GNU Autoconf 2.59.
./libgui/configure:# Generated by GNU Autoconf 2.59.

--
Chuck