scripts: always create lib32 and lib64 symlinks

Unconditionally create the lib32 -> lib/ and lib64 -> lib/ symlinks.

This is reportedly a fix to build a toolchain for a 32-bit target on
a 'pure' 64-bit host (eg. on Fedora FC12, host libs are in lib64/,
and there is no lib -> lib64 symlink, as we can see on other distors,
as Debian). As gcc only puts static host lib in lib64/ (along with
target files in subdirs), we can safely create the symlinks.

Also note that the symlinks are summarily removed at the end
of the build.

Signed-off-by: Anthony Foiani <anthony.foiani@gmail.com>
[Yann E. MORIN: fix a comment, rephrase the commit log]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 Original patch from gentoo: gentoo/src/patchsets/gcc/4.3.1/gentoo/51_all_gcc-3.4-libiberty-pic.patch

 diff -durN gcc-4.3.1.orig/libiberty/Makefile.in gcc-4.3.1/libiberty/Makefile.in

 --- gcc-4.3.1.orig/libiberty/Makefile.in	2007-07-25 08:26:45.000000000 +0200

 +++ gcc-4.3.1/libiberty/Makefile.in	2008-06-10 14:58:02.000000000 +0200

 @@ -225,6 +225,7 @@

  	  $(AR) $(AR_FLAGS) $(TARGETLIB) \

  	    $(REQUIRED_OFILES) $(EXTRA_OFILES) $(LIBOBJS); \

  	  $(RANLIB) $(TARGETLIB); \

 +	  cp $(TARGETLIB) ../ ; \

  	  cd ..; \

  	else true; fi