binary-io, eealloc, mbfile, mbiter, mbutil, xsize: better 'inline'

binary-io, eealloc, mbfile, mbiter, mbutil, xsize: better 'inline'

* lib/binary-io.c, lib/eealloc.c, lib/mbfile.c, lib/mbiter.c:
* lib/mbuiter.c, lib/xsize.c: New files.
* lib/binary-io.h (BINARY_IO_INLINE):
* lib/eealloc.h (EEALLOC_INLINE):
* lib/mbfile.h (MBFILE_INLINE):
* lib/mbiter.h (MBITER_INLINE):
* lib/mbuiter.h (MBUITER_INLINE):
* lib/xsize.h (XSIZE_INLINE):
New macros.
Replace all uses of 'static inline' with them.
Use _GL_INLINE_HEADER_BEGIN, _GL_INLINE_HEADER_END.
* m4/eealloc.m4 (gl_EEALLOC):
* m4/mbfile.m4 (gl_MBFILE):
* m4/mbiter.m4 (gl_MBITER):
* m4/xsize.m4 (gl_XSIZE):
Do not require AC_C_INLINE.
* modules/binary-io (Files, lib_SOURCES): Add lib/binary-io.c
* modules/eealloc (Files, lib_SOURCES): Add lib/eealloc.c.
* modules/mbfile (Files, lib_SOURCES): Add lib/mbfile.c.
* modules/mbiter (Files, lib_SOURCES): Add lib/mbiter.c.
* modules/mbuiter (Files, lib_SOURCES): Add lib/mbuiter.c.
* modules/xsize (Files, lib_SOURCES): Add lib/xsize.c.
* modules/binary-io, modules/eealloc, modules/mbfile:
* modules/mbiter, modules/mbuiter:
(Depends-on): Add extern-inline.