Problems with the installation of XEN 4.14

[Ralf Lehmeier <r.lehmeier@xxxxxxxxxxx>]

I wanted to install XEN under Manajaro from the AUR and so far I got 2 
problems 1. I had to import the key separately, otherwise I got an error 
message and 2. the message :
" ... config.status: linking ./mpn/generic/addsub_n.c to mpn/addsub_n.c
config.status: linking ./mpn/x86_64/addaddmul_1msb0.asm to 
mpn/addaddmul_1msb0.asm
config.status: linking ./mpn/x86_64/gmp-mparam.h to gmp-mparam.h
sed -i 's/#define HAVE_OBSTACK_VPRINTF 1/\/\/#define 
HAVE_OBSTACK_VPRINTF 1/' gmp-x86_64/config.h
touch gmp-x86_64
make[1]: directory "/tmp/trizen-ralf/xen/src/xen-4.14.0/stubdom" is left
make: *** [Makefile:138: install-stubdom] Error 2
==> ERROR: An error occurred in build().
    Abort...
:: Unable to build xen - makepkg exited with code: 4".

now I would like to know how I can get Xen to run anyway.

With kind regards R.Lehmeier