* lib/binary-io.c, lib/math.c, lib/pthread.c, lib/sys_socket.c:
* lib/u64.c, lib/unistd.c:
Append 'typedef int dummy;', to pacify compilers that are picky
about empty translation units.
* lib/sys_socket.c: New file.
* lib/sys_socket.in.h (_GL_SYS_SOCKET_INLINE):
New macro. Replace all uses of 'static inline' with it.
Use _GL_INLINE_HEADER_BEGIN, _GL_INLINE_HEADER_END.
* m4/sys_socket_h.m4 (gl_HEADER_SYS_SOCKET): Do not require AC_C_INLINE.
* modules/sys_socket (Files, lib_SOURCES): Add lib/sys_socket.c.
(Depends-on): Add extern-inline.
