libc/uClibc: move content of do_libc_headers into do_libc_start_files

It is unnecessary to split C library preparation into two steps, as only
one really makes sense. So, do_libc_headers is bound to be withdrawn
short-term, in favor of do_libc_start_files.

uClibc already had all its start files installation in do_libc_headers, and
do_libc_start_files was empty, just migrate the content of the former into
the latter.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 diff -durN gcc-4.4.0.orig/gcc/config/netbsd-elf.h gcc-4.4.0/gcc/config/netbsd-elf.h

 --- gcc-4.4.0.orig/gcc/config/netbsd-elf.h	2007-09-03 18:14:04.000000000 +0200

 +++ gcc-4.4.0/gcc/config/netbsd-elf.h	2009-05-27 21:38:14.000000000 +0200

 @@ -82,6 +82,7 @@

  #define NETBSD_LINK_SPEC_ELF \

    "%{assert*} %{R*} %{rpath*} \

     %{shared:-shared} \

 +   %{symbolic:-Bsymbolic} \

     %{!shared: \

       -dc -dp \

       %{!nostdlib: \