Unable to build deimos/libX11 with ldc2

[Paul Z. Barsan]

    I got ldc2 from github and built it following this tutorial: 
http://wiki.dlang.org/Building_LDC_from_source . The ldc build 
and install went fine but when I try to build libX11 with it, I 
get the following errors:

$make -j2
sh: arch: command not found
Makefile:159: warning: overriding recipe for target `install'
Makefile:156: warning: ignoring old recipe for target `install'
ldc2 -O -d -m64 -L-ldl -m64  -c deimos/X11/Xlibint.d 
-ofbuild/deimos/X11/Xlibint.o
sh: arch: command not found
ldc2 -O -d -m64 -L-ldl -m64  -c deimos/X11/keysym.d 
-ofbuild/deimos/X11/keysym.o
sh: arch: command not found
ldc2 -O -d -m64 -L-ldl -m64  -c deimos/X11/Xproto.d 
-ofbuild/deimos/X11/Xproto.o
sh: arch: command not found
deimos/X11/Xlibint.d(895): Error: Function type does not match 
previously declared function with the same mangled name: Data
make: *** [build/deimos/X11/Xlibint.o] Error 1
make: *** Waiting for unfinished jobs....

Any clues ?