response file support in GCC

[Ralf Wildenhues]

With response file support in GCC [1] we need to adjust Libtool
accordingly.  Minimally to let the option through as below, but
ideally we should probably parse its contents.

Any volunteers?  Comments?

Cheers,
Ralf

[1] http://gcc.gnu.org/ml/gcc-patches/2005-11/msg01700.html

Index: ltmain.in
===================================================================
RCS file: /cvsroot/libtool/libtool/Attic/ltmain.in,v
retrieving revision 1.334.2.97
diff -u -r1.334.2.97 ltmain.in
--- ltmain.in   20 Nov 2005 14:09:00 -0000      1.334.2.97
+++ ltmain.in   24 Nov 2005 08:42:41 -0000
@@ -1548,8 +1548,9 @@
       # -m*, -t[45]*, -txscale* pass through architecture-specific
       # compiler args for GCC
       # -pg pass through profiling flag for GCC
+      # @file GCC response files
       -64|-mips[0-9]|-r[0-9][0-9]*|-xarch=*|-xtarget=*|+DA*|+DD*|-q*|-m*|-pg| \
-      -t[45]*|-txscale*)
+      -t[45]*|-txscale*|@*)
 
        # Unknown arguments in both finalize_command and compile_command need
        # to be aesthetically quoted because they are evaled later.