* environ.h (struct environ): Rename to ...
(struct gdb_environ): ... this.
(make_environ): Update prototype.
(free_environ): Likewise.
(init_environ): Likewise.
(get_in_environ): Likewise.
(set_in_environ): Likewise.
(unset_in_environ): Likewise.
(environ_vector): Likewise.
* environ.c (make_environ): Replace "struct environ" with "struct
gdb_environ".
(free_environ): Likewise.
(init_environ): Likewise.
(environ_vector): Likewise.
(get_in_environ): Likewise.
(set_in_environ): Likewise.
(unset_in_environ): Likewise.
* infcmd.c (inferior_environ): Likewise.
* inferior.h (inferior_environ): Likewise.