[Buildroot] [PATCH] package/xen: fix build failure on x86 after bump to 47

[Yann E. MORIN <yann.morin.1998@free.fr>]

Alistair, All,

On 2016-10-29 16:43 +0200, Yann E. MORIN spake thusly:
> Since the bump to 4.7, Xen fails to build because of a double definition
> of __OBJECT_FILE__. This is due to (who would have guessed) the weirdness
> of their buildsystem.
> 
> Fix that with a dirty hack: undefine the macro before defining it.
> 
> Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> Cc: Alistair Francis <alistair.francis@xilinx.com>
> 
> ---
> Note: totally untested.

Now build-tested, the double-definition issue is fixed, and the build
succeeds with this defconfig:

    BR2_aarch64=y
    BR2_TOOLCHAIN_EXTERNAL=y
    BR2_PACKAGE_XEN=y
    BR2_PACKAGE_XEN_HYPERVISOR=y
    BR2_PACKAGE_XEN_TOOLS=y

Not booted, I don't know Xen enough to test...

Regards,
Yann E. MORIN.

> ---
>  ...mk-fix-build-with-CFLAGS-from-environment.patch | 36 ++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
>  create mode 100644 package/xen/0002-xen-Rules.mk-fix-build-with-CFLAGS-from-environment.patch
> 
> diff --git a/package/xen/0002-xen-Rules.mk-fix-build-with-CFLAGS-from-environment.patch b/package/xen/0002-xen-Rules.mk-fix-build-with-CFLAGS-from-environment.patch
> new file mode 100644
> index 0000000..0d4e581
> --- /dev/null
> +++ b/package/xen/0002-xen-Rules.mk-fix-build-with-CFLAGS-from-environment.patch
> @@ -0,0 +1,36 @@
> +From 2a310549aaeaba05f640ade43488bb893101ce4a Mon Sep 17 00:00:00 2001
> +From: "Yann E. MORIN" <yann.morin.1998@free.fr>
> +Date: Sat, 29 Oct 2016 16:35:26 +0200
> +Subject: [PATCH] xen/Rules.mk: fix build with CFLAGS from environment
> +
> +When CFLAGS are passed from the environment, the first-level make
> +invocation will append -D__OBJECT_FILE__ to it, then call a second
> +make invocation, that will have those new CFLAGS in its environment,
> +but will also append -D__OBJECT_FILE__ to those.
> +
> +Then, the compiler fails because __OBEJECT_FILE__ is defined twice.
> +
> +Just undefine it before defining it again, as a *workaround* to this
> +issue.
> +
> +Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
> +---
> + xen/Rules.mk | 2 +-
> + 1 file changed, 1 insertion(+), 1 deletion(-)
> +
> +diff --git a/xen/Rules.mk b/xen/Rules.mk
> +index a9fda71..09ccbfa 100644
> +--- a/xen/Rules.mk
> ++++ b/xen/Rules.mk
> +@@ -49,7 +49,7 @@ ALL_OBJS-$(CONFIG_CRYPTO)   += $(BASEDIR)/crypto/built_in.o
> + CFLAGS += -nostdinc -fno-builtin -fno-common
> + CFLAGS += -Werror -Wredundant-decls -Wno-pointer-arith
> + CFLAGS += -pipe -g -D__XEN__ -include $(BASEDIR)/include/xen/config.h
> +-CFLAGS += '-D__OBJECT_FILE__="$@"'
> ++CFLAGS += -U__OBJECT_FILE__ '-D__OBJECT_FILE__="$@"'
> + 
> + ifneq ($(clang),y)
> + # Clang doesn't understand this command line argument, and doesn't appear to
> +-- 
> +2.7.4
> +
> -- 
> 2.7.4
> 

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