conflict with C99 functions which are builtins in newer gcc
(actually, the old cabs() is ABI compatible with the new _complex one
on i386, but this is purely accidental)
remove public prototypes and manpages, move the code into a compat
subdirectory as libc does so that binary compatibility is kept
-add a manpage for the isgreater() etc macros, borrowed from FreeBSD
7161d089aa