Re: [PATCH] fix qemu building with older make

[George Dunlap <george.dunlap@eu.citrix.com>]

On 07/28/2014 10:25 AM, Jan Beulich wrote:
> The $(or ) builtin (uses introduced by commits ffbf089357 and
> 8962a8f951) is supported only from make 3.81 onwards, yet we claim to
> only require make 3.80. Introduce a good enough fallback.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

I don't really know enough about make to have an opinion on the code 
itself; but re the idea:

Acked-by: George Dunlap <george.dunlap@eu.citrix.com>

>
> --- a/Config.mk
> +++ b/Config.mk
> @@ -12,6 +12,7 @@ space   := $(empty) $(empty)
>
>   # fallback for older make
>   realpath = $(wildcard $(foreach file,$(1),$(shell cd -P $(dir $(file)) && echo "$$PWD/$(notdir $(file))")))
> +or       = $(if $(strip $(1)),$(1),$(if $(strip $(2)),$(2),$(if $(strip $(3)),$(3),$(if $(strip $(4)),$(4)))))
>
>   -include $(XEN_ROOT)/.config
>
> @@ -266,11 +267,11 @@ QEMU_TRADITIONAL_REVISION ?= d0395cc49b2
>   # QEMU_UPSTREAM_LOC ?= `pwd`/$(XEN_ROOT)/../qemu-xen.git
>
>   # Defaults for subtree locations
> -QEMU_TRADITIONAL_LOC ?= $(or $(wildcard $(QEMU_TRADITIONAL_INTREE)),\
> -                        $(QEMU_TRADITIONAL_URL))
> -
> -QEMU_UPSTREAM_LOC ?= $(or $(wildcard $(QEMU_UPSTREAM_INTREE)),\
> -                        $(QEMU_UPSTREAM_URL))
> +QEMU_TRADITIONAL_LOC ?= $(call or,$(wildcard $(QEMU_TRADITIONAL_INTREE)),\
> +                                  $(QEMU_TRADITIONAL_URL))
> +
> +QEMU_UPSTREAM_LOC ?= $(call or,$(wildcard $(QEMU_UPSTREAM_INTREE)),\
> +                               $(QEMU_UPSTREAM_URL))
>
>   # Short answer -- do not enable this unless you know what you are
>   # doing and are prepared for some pain.
>
>
>