uclibc: fix undefinition of '_dl_strchr' in libdl.a

uclibc: fix undefinition of '_dl_strchr' in libdl.a

The orign_path.patch introduced '_dl_strchr' in ldso/ldso/dl-elf.c, and
caused the following undefined referencing compiling error:

  | .../libdl.a(libdl.os): In function `search_for_named_library':
  | .../dl-elf.c:156: undefined reference to `_dl_strchr'
  | collect2: error: ld returned 1 exit status

I found this problem when compiling gdb in static mode using uclibc.

So, add the definition of '_dl_strchr' to fix it. The '_dl_strstr' is
added as well.

And I regenerated a patch to replace the original one.

(From OE-Core master rev: 34b82b8452aa721146f95321cfd1a1fee3f0d6c8)

Signed-off-by: Junling Zheng <zhengjunling@huawei.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>