[toplevel] Import two libtool patches to simplify AC_DEPLIBS_CHECK_METHODunder Linux.

[Kelley Cook <kcook at gcc dot gnu dot org>]

I would like to propose to import these two patches from libtool which 
gets rid of the special casing for Linux dependencies. From the first 
patch states that the casing for arm was never correct.  The second 
patch just eliminates the dead code caused by the first one.

http://lists.gnu.org/archive/html/libtool-patches/2003-09/msg00042.html
http://lists.gnu.org/archive/html/libtool-patches/2004-08/msg00062.html

A little research will show that this should eliminate the hack (which 
was essentially yet another copy of libtool) that was put in libmudtool 
( http://gcc.gnu.org/ml/gcc-patches/2003-06/msg00239.html ) by the 
fairly elegant, and quasi-approved, patch to eliminate libmudflap's 
acinclude.m4 proposed at http://gcc.gnu.org/ml/gcc/2004-11/msg00629.html

But without this libtool patch, I question if eliminating the duplicity 
would properly work on x86-64 GNU/linux.

OK?

Bootstrapped on i686-pc-linux-gnu after regenerating every directory 
that used libtool.
2004-11-24  Kelley Cook  <kcook@gcc.gnu.org>

	* libtool.m4 (AC_DEPLIBS_CHECK_METHOD): Import linux-gnu case
	from CVS libtool to always pass_all.

Index: libtool.m4
===================================================================
RCS file: /cvs/gcc/gcc/libtool.m4,v
retrieving revision 1.16
diff -p -u -d -c -r1.16 libtool.m4
*** libtool.m4	18 May 2004 10:11:24 -0000	1.16
--- libtool.m4	24 Nov 2004 03:20:48 -0000
*************** irix5* | irix6*)
*** 679,692 ****
  
  # This must be Linux ELF.
  linux-gnu*)
!   case $host_cpu in
!   alpha* | mips* | hppa* | i*86 | powerpc* | sparc* | ia64* | sh* )
!     lt_cv_deplibs_check_method=pass_all ;;
!   *)
!     # glibc up to 2.1.1 does not perform some relocations on ARM
!     lt_cv_deplibs_check_method=['file_magic ELF [0-9][0-9]*-bit [LM]SB (shared object|dynamic lib )'] ;;
!   esac
!   lt_cv_file_magic_test_file=`echo /lib/libc.so* /lib/libc-*.so`
    ;;
  
  netbsd* | knetbsd*-gnu)
--- 679,685 ----
  
  # This must be Linux ELF.
  linux-gnu*)
!   lt_cv_deplibs_check_method=pass_all
    ;;
  
  netbsd* | knetbsd*-gnu)