Support for NetBSD.

* aclocal.m4: Add test for NetBSD's ctype support.
* configure: Regenerate.
* configure.target: Support NetBSD.
* config/os/netbsd/bits/ctype_base.h: New file.
* config/os/netbsd/bits/ctype_inline.h: New file.
* config/os/netbsd/bits/ctype_noinline.h: New file.
* config/os/netbsd/bits/os_defines.h: New file.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@38032 138bc75d-0d04-0410-961f-82ee72b054a4