Originally reported by Dan Horák,

Since vzctl will still build all the vz-kernel support even if the goal is running on upstream Linux kernels, it won't build on all secondary arches.

build.log says:

...
In file included from cpu.c:31:0:
../../include/vzsyscalls.h:66:2: error: #error "no syscall for this arch"
cpu.c: In function 'fairsched_chwt':
cpu.c:37:16: error: '__NR_fairsched_chwt' undeclared (first use in this function)
cpu.c:37:16: note: each undeclared identifier is reported only once for each function it appears in
cpu.c: In function 'fairsched_rate':
cpu.c:47:16: error: '__NR_fairsched_rate' undeclared (first use in this function)
cpu.c: In function 'fairsched_vcpus':
cpu.c:57:16: error: '__NR_fairsched_vcpus' undeclared (first use in this function)
make[2]: *** [cpu.lo] Error 1

and same error should occur on ARM and PPC64. Nothing critical, I've excluded vzctl in s390 build system now, the other secondary arch maintainers will do the same, but nice to have in the future I think.