sync libctf toplevel from binutils-gdb

This pulls in the toplevel portions of these binutils-gdb commits:

   1ff6de031241c59d0ff bfd, ld: add CTF section linking
   87279e3cef5b2c54f4a libctf: installable libctf as a shared library
   c59e30ed1727135f8ef libctf: new testsuite

	* Makefile.def: Sync with binutils-gdb:
	(dependencies): all-ld depends on all-libctf.
	(host_modules): libctf is no longer no_install.
	No longer no_check.  Checking depends on all-ld.
	* Makefile.in: Regenerated.