xdm uses arc4random and setproctitle without proper includes
Submitted by Chí-Thanh Christopher Nguyễn
Assigned to Xorg Project Team
Created attachment 91543 build.log from Gentoo
According to arc4random(3), on BSD or OS X #include <stdlib.h> while on Linux systems with libbsd, #include <bsd/stdlib.h> is needed.
A similar issue exists with setproctitle(3). This will cause the compiler to complain about implicit function declarations.
Attachment 91543, "build.log from Gentoo":