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 So, do_libc_headers is bound to be withdrawn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-4.4.4.orig/libstdc++-v3/include/c_global/cstdio gcc-4.4.4/libstdc++-v3/include/c_global/cstdio

--- gcc-4.4.4.orig/libstdc++-v3/include/c_global/cstdio	2009-04-10 01:23:07.000000000 +0200

+++ gcc-4.4.4/libstdc++-v3/include/c_global/cstdio	2010-05-16 19:37:06.000000000 +0200

@@ -139,7 +139,7 @@

 _GLIBCXX_END_NAMESPACE

-#if _GLIBCXX_USE_C99

+#if _GLIBCXX_USE_C99 || defined __UCLIBC__

 #undef snprintf

 #undef vfscanf