Re: kbuild variable $(src) broken in 2.6.23-rc3?

[Andrea Arcangeli <andrea@qumranet.com>]

On Wed, May 21, 2008 at 09:04:53PM +0200, Sam Ravnborg wrote:
> Andrea Arcangeli <andrea@qumranet.com> reported a similar issue.
> I have not gotten around to look at it yet.
> I minimal Makefile that exhibits the problem
> would be helpfull!

I don't have the minimal but I can easily provide you a way to
reproduce:

git clone git://git.kernel.org/pub/scm/virt/kvm/kvm-userspace.git
cd kvm-userspace
patch -p1 -R <../belowinlinedworkaround
./configure --kerneldir=/usr/src/anykernel
cd kernel
make

The below has the benefit of making more robust and higher prio the
inclusion of external-module-compat so it may not to be backed out
after this 2.6.26-rc regression is fixed.

The problem is that the $(src) in the EXTRA_CFLAGS below is expanded
to "".

Thanks.

Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>

diff --git a/kernel/Kbuild b/kernel/Kbuild
index cabfc75..d9245eb 100644
--- a/kernel/Kbuild
+++ b/kernel/Kbuild
@@ -1,4 +1,3 @@
-EXTRA_CFLAGS := -I$(src)/include -include $(src)/external-module-compat.h
 obj-m := kvm.o kvm-intel.o kvm-amd.o
 kvm-objs := kvm_main.o x86.o mmu.o x86_emulate.o anon_inodes.o irq.o i8259.o \
 	 lapic.o ioapic.o preempt.o i8254.o external-module-compat.o
diff --git a/kernel/Makefile b/kernel/Makefile
index 78ff923..e3fccbe 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -27,7 +27,8 @@ all::
 #	include header priority 1) $LINUX 2) $KERNELDIR 3) include-compat
 	$(MAKE) -C $(KERNELDIR) M=`pwd` \
 		LINUXINCLUDE="-I`pwd`/include -Iinclude -I`pwd`/include-compat \
-		-include include/linux/autoconf.h" \
+		-include include/linux/autoconf.h \
+		-include `pwd`/external-module-compat.h"
 		"$$@"
 
 sync: header-sync source-sync