[PATCH v2] kbuild, deb-pkg: support overriding userland architecture

[Asbjoern Sloth Toennesen <asbjorn@asbjorn.biz>]

Usefull if building for sparc64 userland, because the
sparc and sparc64 userlands use the same 64-bit kernel,
making it impossible to always select the correct userland
architecture for the resulting debian package.

Might also be usefull, if you want a i386 userland with a amd64 kernel.

Example usage:
	make DEBARCH=i386 deb-pkg

LKML-reference: <alpine.DEB.2.02.1011051437500.13287@aurora.sdinet.de>
Signed-off-by: Asbjoern Sloth Toennesen <asbjorn@asbjorn.biz>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: maximilian attems <max@stro.at>
---
 Documentation/kbuild/kbuild.txt |    8 ++++++++
 scripts/package/builddeb        |    3 +++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index 634c625..2940df0 100644
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -60,6 +60,14 @@ But some architectures such as x86 and sparc have aliases.
 x86: i386 for 32 bit, x86_64 for 64 bit
 sparc: sparc for 32 bit, sparc64 for 64 bit
 
+DEBARCH
+--------------------------------------------------
+For the deb-pkg target, allows overriding the normal heuristics deployed by
+deb-deb. Normally deb-pkg attempts to guess the right architecture based on
+the UTS_MACHINE variable, and on some architectures also the kernel config.
+The value of DEBARCH is assumed (not checked) to be a valid Debian
+architecture.
+
 CROSS_COMPILE
 --------------------------------------------------
 Specify an optional fixed part of the binutils filename.
diff --git a/scripts/package/builddeb b/scripts/package/builddeb
index 5d6be3f..22b6995 100644
--- a/scripts/package/builddeb
+++ b/scripts/package/builddeb
@@ -54,6 +54,9 @@ create_package() {
 		echo "Please add support for $UTS_MACHINE to ${0} ..." >&2
 		echo "" >&2
 	esac
+	if [ -n "$DEBARCH" ] ; then
+		debarch="$DEBARCH"
+	fi
 	if [ -n "$debarch" ] ; then
 		forcearch="-DArchitecture=$debarch"
 	fi
-- 
1.7.2.3