gcc3 does not compile

[Dariusz Marcinkiewicz <dmarcink@elka.pw.edu.pl>]

	I'm trying to compile gcc3.0 on openbsd2.9stable/x86.
During the compilation an "old"  gcc  reports that following
lines in /usr/include/sys/endian.h have wrong sytnax:

__BEGIN_DECLS
u_int32_t	htobe32 __P((u_int32_t));
u_int16_t	htobe16 __P((u_int16_t));
u_int32_t	betoh32 __P((u_int32_t));
u_int16_t	betoh16 __P((u_int16_t));

u_int32_t	htole32 __P((u_int32_t));
u_int16_t	htole16 __P((u_int16_t));
u_int32_t	letoh32 __P((u_int32_t));
u_int16_t	letoh16 __P((u_int16_t));
__END_DECLS


How can I solve this problems, should I modify this file?
For me this syntax is alslo odd, can anyone explain what this
strange definitions mean i.e. this __P and __BEGIN_DECS, __END_DECLS
are there macros or something?

Thanks in advance,

DM