make fails because it doesn't know “headers_install”

Question

I'm trying to setup buildroot for cross-compiling a custom app.

/ # uname -a
Linux Venus 2.6.12.6-VENUS #323634 Wed May 25 13:40:36 CST 2011 mips unknown

So far I chose kernel version 2.6.12.6 in buildroot. Now I've got the problem that the make command fails yelling that the rule headers_install is unknown.

Here is the compleat output:

~/buildroot-2011.11$ make
(cd /root/buildroot-2011.11/output/toolchain/linux-2.6.12.6; \
         /usr/bin/make -j2 ARCH=mips \
                HOSTCC="/usr/bin/gcc" HOSTCFLAGS="" \
                HOSTCXX="/usr/bin/g++" \
                INSTALL_HDR_PATH=/root/buildroot-2011.11/output/toolchain/linux headers_install; \
        )
make[1]: Entering directory `/root/buildroot-2011.11/output/toolchain/linux-2.6.12.6'
Makefile:485: .config: Datei oder Verzeichnis nicht gefunden
make[1]: *** Keine Regel, um »headers_install« zu erstellen.  Schluss.
make[1]: Leaving directory `/root/buildroot-2011.11/output/toolchain/linux-2.6.12.6'
make: *** [/root/buildroot-2011.11/output/toolchain/linux/.configured] Fehler 2

I think the problem is that this old kernel doesn't have this option in its makefile.

What should I do?

---

I took a look at the 3.2.6 kernel makefile. I found there:

headers_install: __headers
    $(if $(wildcard $(srctree)/arch/$(hdr-arch)/include/asm/Kbuild),, \
    $(error Headers not exportable for the $(SRCARCH) architecture))
    $(Q)$(MAKE) $(hdr-inst)=include
    $(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/asm $(hdr-dst)

That seems to call a second makefile called Makefile.headersinst.

But what does that one do?

---

I tried to use the Makefile and the scripts directory of the new kernel 3.2.6 by replacing the old one.

Here is the output:

# make
(cd /root/buildroot-2011.11/output/toolchain/linux-2.6.12.6; \
         /usr/bin/make -j2 ARCH=mips \
                HOSTCC="/usr/bin/gcc" HOSTCFLAGS="" \
                HOSTCXX="/usr/bin/g++" \
                INSTALL_HDR_PATH=/root/buildroot-2011.11/output/toolchain/linux headers_install; \
        )
make[1]: Entering directory `/root/buildroot-2011.11/output/toolchain/linux-2.6.12.6'
  CHK     include/linux/version.h
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/unifdef
Makefile:1059: *** Headers not exportable for the mips architecture.  Schluss.
make[1]: Leaving directory `/root/buildroot-2011.11/output/toolchain/linux-2.6.12.6'
make: *** [/root/buildroot-2011.11/output/toolchain/linux/.configured] Fehler 2

No idea what I can try now.