problem with xlib

[How Wong]

when I used g++ from gcc2.95 ansi c++ needs extern function to have type
in Xlib.h, but
and produce messages like these

/usr/X11R6/include/X11/Xlib.h:2132: ANSI C++ forbids declaration
`XSetTransientForHin
t' with no type
/usr/X11R6/include/X11/Xlib.h:2140: ANSI C++ forbids declaration
`XActivateScreenSave
r' with no type
/usr/X11R6/include/X11/Xlib.h:2147: ANSI C++ forbids declaration
`XAddHost' with no type no type

but gcc2.8.1 does not produce these messages
How do I fix it?