building libXt: undefined datarootdir

[Lars Noschinski]

Hello!

I'm trying to build xorg from git with latest build.sh and I'm getting
the following warning:

| config.status: creating xt.pc
| config.status: WARNING: xt.pc contains a reference to the variable `datarootdir'
| which seems to be undefined.  Please make sure it is defined.

Some occurs also for XCursor. This causes some other packages to fail to build:

| checking for XSERVERCFLAGS... configure: error: Package requirements
| (randrproto renderproto fixesproto >= 4.0 dama geproto xcmiscproto xextproto
| xproto xtrans xf86miscproto xf86vidmodeproto xf86bigfontproto scrnsaverproto >=
| 1.1 b igreqsproto resourceproto fontsproto inputproto xf86dgaproto videoproto
| compositeproto >= 0.3 trapproto recordproto resourceproto xineramaproto
| evieproto printproto xkbfile xfont xau fontenc xdmcp) were not met:
| 
| Variable 'datarootdir' not defined in '/home/lars/tmp/build-xorg/lib/pkgconfig/xt.pc'
| 
| Consider adjusting the PKG_CONFIG_PATH environment variable if you
| installed software in a non-standard prefix.

The generated xt.pc looks like the following:

| prefix=/home/lars/tmp/build-xorg
| exec_prefix=${prefix}
| libdir=${exec_prefix}/lib
| includedir=${prefix}/include
| appdefaultdir=${datarootdir}/X11/app-defaults
| 
| Name: Xt
| Description: X Toolkit Library
| Version: 1.0.2
| Requires: xproto x11 sm
| Requires.private: x11 sm
| Cflags: -I${includedir}
| Libs: -L${libdir} -lXt

autoconf is version 2.59e