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

[Charles Wilson]

Andreas Schwab wrote:
> Charles Wilson <cygwin@cwilson.fastmail.fm> writes:
> 
>> 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. I think it was because the top-level configure
>> automatically augmented it as follows, when the var was originally empty:
>>
>>   X="$X --some-new-flag"
>>
>> For some reason, the sub-configure had the variable without the leading
>> space, so it complained of a mismatch.
> 
> That should no longer be an issue with the switch to autoconf 2.64.
> Such whitespace differences are now ignored.

Ah:
$ find . -name "configure"|\
	xargs grep 'Generated by GNU Autoconf' | grep -v 2.64

./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.

Looks like some stuff missed regeneration?

--
Chuck