configure gdb/gnulib with --disable-largefile if largefile support disabled.

configure gdb/gnulib with --disable-largefile if largefile support disabled.

This patch mostly aims at fixing a GDB build failure on 32bit Solaris
systems (Sparc and x86), due to a recent gnulib update adding the
readlink module. But it might also fix related issues when configuring
with --disable-largefile.

A side-effect of the gnulib readlink module addition is that it caused
largefile support to be added as well, and in particular
gnulib/import/m4/largefile.m4 introduced the following new #define in
gnulib's config.in:

| +/* Number of bits in a file offset, on hosts where this is settable. */
| +#undef _FILE_OFFSET_BITS

When defined to 64, it triggers an issue with procfs.h while trying
to build sparc-sol2-nat.c:

| #if !defined(_LP64) && _FILE_OFFSET_BITS == 64
| #error  "Cannot use procfs in the large file compilation environment"
| #endif

As it turns out, this is a fairly familiar problem, and one of
the reasons behind ACX_LARGEFILE having been created. In that macro,
we have some code which disables largefile support on solaris hosts:

|   sparc-*-solaris*|i[3-7]86-*-solaris*)
| changequote([,])dnl
|     # On native 32bit sparc and ia32 solaris, large-file and procfs support
|     # are mutually exclusive; and without procfs support, the bfd/ elf module
|     # cannot provide certain routines such as elfcore_write_prpsinfo
|     # or elfcore_write_prstatus.  So unless the user explicitly requested
|     # large-file support through the --enable-largefile switch, disable
|     # large-file support in favor of procfs support.
|     test "${target}" = "${host}" -a "x$plugins" = xno \
|       && : ${enable_largefile="no"}
|     ;;

But gnulib ignores this fact, and so tries to determine how to
enable large-file support irrespective of whether we want it or not.
This patch fixes the issue by passing --disable-largefile to gnulib's
configure when large-file support in GDB is disabled. This is done
by first enhancing ACX_CONFIGURE_DIR to allow us to pass extra
arguments to be passed to the configure command, and then by modifying
GDB's configure to pass --disable-largefile if large-file support
is disabled.

gdb/ChangeLog:

	* acx_configure_dir.m4 (ACX_CONFIGURE_DIR): Add support for
        new "EXTRA-ARGS" parameter.
	* configure.ac: If large-file support is disabled in GDB,
        pass --disable-largefile to ACX_CONFIGURE_DIR call for "gnulib".
	* configure: Regenerate.

gdb/gdbserver/ChangeLog:

	* configure.ac: If large-file support is disabled in GDBserver,
        pass --disable-largefile to ACX_CONFIGURE_DIR call for "gnulib".
        * configure: Regenerate.

Tested by rebuilding on sparc-solaris and x86_64-linux (with gdbserver).
This fixes the build failure on sparc-solaris. I also verified in
gnulib's config.log file that we pass --disable-largefile in the solaris
case, while we do not in the GNU/Linux case.