maint: missing declaration.
maint: missing declaration.

* ext/posix/fcntl.c (Pposix_fadvise): Add missing declaration.

Signed-off-by: Gary V. Vaughan <f9023000f29773649f3850298becb9544b5fd6a9@gnu.org>

zevv/luaposix,snegovick/luaposix,ardje/luaposix,luaposix/luaposix,jimmyharris/luaposix,jimmyharris/luaposix,zevv/luaposix,rrthomas/luaposix,snegovick/luaposix,ardje/luaposix,rrthomas/luaposix