kerneldev: create kernel-devsrc packaging

kernel-devsrc is responsible for creating and a packaging an environment
appropriate for kernel development (on or off target).

To create this support, we only need to copy/install the results of the
virtual/kernel providers build in the staging dir ... with some minor
manipulations to the source tree (.git removal and a clean up). This
produces a source tree that is capable of rebuilding the kernel on the
target.

Installing the kernel-devsrc package on a target (along with a
toolchain) is all that remains to be done.

 $ cd /usr/src/kernel
 $ make oldconfig
 $ make -j2 bzImage

(From OE-Core rev: 6412dc1df434f774c434ec08bf9b3706edb756f2)

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-kernel/linux/kernel-devsrc.bb

@@ -0,0 +1,50 @@
+SUMMARY = "Linux kernel Development Source"
+DESCRIPTION = "Development source linux kernel. When built, this recipe packages the \
+source of the preferred virtual/kernel provider and makes it available for full kernel \
+development or external module builds"
+
+SECTION = "kernel"
+
+LICENSE = "GPLv2"
+LIC_FILES_CHKSUM = "file://${COMMON_LICENSE_DIR}/GPL-2.0;md5=801f80980d171dd6425610833a22dbe6"
+
+inherit linux-kernel-base
+
+# We need the kernel to be staged (unpacked, patched and configured) before
+# we can grab the source and make the kernel-devsrc package
+do_install[depends] += "virtual/kernel:do_populate_sysroot"
+
+# There's nothing to do here, except install the source where we can package it
+do_fetch[noexec] = "1"
+do_unpack[noexec] = "1"
+do_patch[noexec] = "1"
+do_configure[noexec] = "1"
+do_compile[noexec] = "1"
+do_populate_sysroot[noexec] = "1"
+
+# Define where the kernel headers are installed on the target as well as where
+# they are staged.
+KERNEL_SRC_PATH = "/usr/src/kernel"
+S = "${STAGING_DIR_TARGET}/${KERNEL_SRC_PATH}"
+
+KERNEL_VERSION = "${@get_kernelversion_headers('${S}')}"
+
+PACKAGE_ARCH = "${MACHINE_ARCH}"
+
+do_install() {
+        kerneldir=${D}${KERNEL_SRC_PATH}
+        install -d $kerneldir
+
+        #
+        # Copy the staging dir source (and module build support) into the devsrc structure.
+        # We can keep this copy simple and take everything, since a we'll clean up any build
+        # artifacts afterwards, and the extra i/o is not significant
+        #
+        cd ${S}
+        find . -type d -name '.git*' -prune -o -type f -print0 | cpio --null -pdlu $kerneldir
+        oe_runmake -C $kerneldir CC="${KERNEL_CC}" LD="${KERNEL_LD}" clean _mrproper_scripts
+}
+
+PACKAGES = "kernel-devsrc"
+FILES_${PN} = "${KERNEL_SRC_PATH}"
+RDEPENDS_${PN} = "bc"