I have had no problems compiling xorg 6.7.0. So I figured 6.8.0 shouldn't be any different. Well it seems to be. It keeps failing the compile after leaving the "dmx" directory. It appears to be something in the libloader directory but I am at a loss to determine the exact problem. Poking through the README and INSTALL files throughout the "xc" directories have not been helpful nor has Google.

make[5]: Leaving directory `/usr/src/xc/programs/Xserver/hw/dmx'
gcc -m32 -o Xorg -O2 -mcpu=i686 -march=i686 -mmmx -msse -mfpmath=sse,387 -O2 -mcpu=i686 -march=i686 -mmmx -msse -mfpmath=sse,387 -L../../exports/lib xkb/xf86KillSrv.o xkb/xf86VT.o xkb/xf86Private.o ../../programs/Xserver/hw/xfree86/common/xf86Init.o ../../programs/Xserver/hw/xfree86/common/xf86IniExt.o ../../programs/Xserver/hw/xfree86/common/libxf86.a ../../programs/Xserver/hw/xfree86/parser/libxf86config.a ../../programs/Xserver/hw/xfree86/os-support/libxf86_os.a ../../programs/Xserver/hw/xfree86/loader/libloader.a ../../programs/Xserver/hw/xfree86/common/libxf86.a dix/libdix.a os/libos.a ../../lib/font/fontbase.o ../../lib/font/libfontbase.a Xext/libexts.a xkb/libxkb.a Xi/libxinput.a lbx/liblbx.a ../../lib/lbxutil/liblbxutil.a ../../programs/Xserver/hw/xfree86/common/libxf86.a composite/libcomposite.a damageext/libdamage.a miext/damage/libdamage.a xfixes/libxfixes.a miext/cw/libcw.a Xext/libexts.a xkb/libxkb.a Xi/libxinput.a lbx/liblbx.a ../../lib/lbxutil/liblbxutil.a randr/librandr.a render/librender.a dix/libxpstubs.a mi/libmi.a composite/libcomposite.a damageext/libdamage.a miext/damage/libdamage.a xfixes/libxfixes.a miext/cw/libcw.a Xext/libexts.a xkb/libxkb.a Xi/libxinput.a lbx/liblbx.a ../../lib/lbxutil/liblbxutil.a randr/librandr.a render/librender.a ../../programs/Xserver/hw/xfree86/os-support/libxf86_os.a -lz -lm -lXau -lXdmcp -rdynamic -ldl -Wl,-rpath-link,../../exports/lib
../../programs/Xserver/hw/xfree86/loader/libloader.a(xf86sym.o)(.data+0x1274): undefined reference to `__stack_smash_handler'
../../programs/Xserver/hw/xfree86/loader/libloader.a(xf86sym.o)(.data+0x127c): undefined reference to `__guard'
collect2: ld returned 1 exit status
make[4]: *** [Xorg] Error 1
make[4]: Leaving directory `/usr/src/xc/programs/Xserver'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/usr/src/xc/programs'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/usr/src/xc'
make[1]: *** [World] Error 2
make[1]: Leaving directory `/usr/src/xc'
make: *** [World] Error 2