[patch] config.gcc: Clear more variables at top

[Nathanael Nerode]

The problem here is that these aren't set by every machine (some use the
default values, set later in configure.in).  Accordingly, when one is set
by a BUILD machine, it overrides the defaults for the HOST and TARGET
machines, which is almost certainly wrong.

I've been considering breaking the file up so that it isn't run through
three times; but in the course of doing that I ran into things which are
simple errors, like this.  So I'm dealing with those now.

Bootstrapped i686-pc-linux-gnu.

	* config.gcc: Clear xm_file, md_file at the beginning of each pass.

Index: config.gcc
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config.gcc,v
retrieving revision 1.288
diff -u -r1.288 config.gcc
--- config.gcc	28 Feb 2003 18:17:33 -0000	1.288
+++ config.gcc	21 Mar 2003 03:26:29 -0000
@@ -224,6 +224,9 @@
 target_gtfiles=
 need_64bit_hwint=
 
+# Don't carry these over build->host->target.  Please.
+xm_file=
+
 # Obsolete configurations.
 case $machine in
    m88k-*-aout*     \
Index: config.gcc
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config.gcc,v
retrieving revision 1.288
diff -u -r1.288 config.gcc
--- config.gcc	28 Feb 2003 18:17:33 -0000	1.288
+++ config.gcc	21 Mar 2003 03:48:20 -0000
@@ -224,6 +224,10 @@
 target_gtfiles=
 need_64bit_hwint=
 
+# Don't carry these over build->host->target.  Please.
+xm_file=
+md_file=
+
 # Obsolete configurations.
 case $machine in
    m88k-*-aout*     \