Apply attribute returns_nonnull in libiberty

[Marc Glisse]

Hello,

here are some uses for returns_nonnull in libiberty.

Bootstrap+testsuite (default languages) on x86_64-unknown-linux-gnu.

2013-10-11  Marc Glisse  <marc.gli...@inria.fr>

        PR tree-optimization/58689
include/
        * ansidecl.h (ATTRIBUTE_RETURNS_NONNULL): New macro.
        * libiberty.h (basename, lbasename, dos_lbasename, unix_lbasename,
        concat_copy): Mark with attributes nonnull(1) and returns_nonnull.
        (concat, reconcat, concat_copy2, choose_temp_base, xstrerror,
        xmalloc, xrealloc, xcalloc, xstrdup, xstrndup, xmemdup, pex_init):
        Mark with attribute returns_nonnull.

libiberty/
        * concat.c: Remove note about xmalloc.

--
Marc Glisse