scratch_buffer: don’t use private glibc API
Suggested by Florian Weimer in:
http://lists.gnu.org/archive/html/bug-gnulib/2017-09/msg00004.html
* lib/scratch_buffer.h: Rename to lib/malloc/scratch_buffer.h.
* lib/scratch_buffer_grow.c: Rename to
lib/malloc/scratch_buffer_grow.c.
* lib/scratch_buffer_grow_preserve.c: Rename to
lib/malloc/scratch_buffer_grow_preserve.c.
* lib/scratch_buffer_set_array_size.c: Rename to
lib/malloc/scratch_buffer_set_array_size.c.
* lib/scratch_buffer.h: New file.
* modules/scratch_buffer (Files, Makefile.am):
Adjust to source-file renaming.