Align Kconfig and Kbuild logic to Linux 4.19 release with minimal impact
on files outside of this scope.
Our previous Kconfig sync was done by commit 5972ff077e ("kconfig /
kbuild: re-sync with Linux 4.18").
In this particular re-sync in order to keep clang support working a
number of related changes needed to be pulled in that had been missed
previously. Not all of these changes we easily traceable and so have
been omitted from the list below.
The imported Linux commits are:
[From prior to v4.18]
9f3f1fd29976 kbuild: Add __cc-option macro
d7f14c66c273 kbuild: Enable Large File Support for hostprogs
6d79a7b424a5 kbuild: suppress warnings from 'getconf LFS_*'
24403874316a Shared library support
86a9df597cdd kbuild: fix linker feature test macros when cross compiling with Clang
0294e6f4a000 kbuild: simplify ld-option implementation
[From v4.18 to v4.19]
96f14fe738b6 kbuild: Rename HOSTCFLAGS to KBUILD_HOSTCFLAGS
10844aebf448 kbuild: Rename HOSTCXXFLAGS to KBUILD_HOSTCXXFLAGS
b90a368000ab kbuild: Rename HOSTLDFLAGS to KBUILD_HOSTLDFLAGS
8377bd2b9ee1 kbuild: Rename HOST_LOADLIBES to KBUILD_HOSTLDLIBS
f92d19e0ef9b kbuild: Use HOST*FLAGS options from the command line
4ab3b80159d4 kconfig: check for pkg-config on make {menu,n,g,x}config
693359f7ac90 kconfig: rename SYMBOL_AUTO to SYMBOL_NO_WRITE
f60b992e30ff kbuild: replace $(LDFLAGS) $(ldflags-y) with $(ld_flags)
2fb9279f2c3e kbuild: change ld_flags to contain LDFLAGS_$(@F)
c931d34ea085 arm64: build with baremetal linker target instead of Linux when available
5accd7f3360e kconfig: handle format string before calling conf_message_callback()
a2ff4040151a kconfig: rename file_write_dep and move it to confdata.c
0608182ad542 kconfig: split out useful helpers in confdata.c
adc18acf42a1 kconfig: remove unneeded directory generation from local*config
79123b1389cc kconfig: create directories needed for syncconfig by itself
16952b77d8b5 kconfig: make syncconfig update .config regardless of sym_change_count
d6c6ab93e17f kbuild: remove deprecated host-progs variable
56869d45e364 kconfig: fix the rule of mainmenu_stmt symbol
c151272d1687 kconfig: remove unused sym_get_env_prop() function
1880861226c1 kconfig: remove P_ENV property type
e3fd9b5384f3 scripts/dtc: consolidate include path options in Makefile
4bf6a9af0e91 kconfig: add build-only configurator targets
f1575595d156 kconfig: error out when seeing recursive dependency
5e8c5299d315 kconfig: report recursive dependency involving 'imply'
f498926c47aa kconfig: improve the recursive dependency report
98a4afbfafd2 kconfig: fix "Can't open ..." in parallel build
9a9ddcf47831 kconfig: suppress "configuration written to .config" for syncconfig
87a32e624037 kbuild: pass LDFLAGS to recordmcount.pl
d503ac531a52 kbuild: rename LDFLAGS to KBUILD_LDFLAGS
217c3e019675 disable stringop truncation warnings for now
bc8d2e20a3eb kconfig: remove a spurious self-assignment
fd65465b7016 kconfig: do not require pkg-config on make {menu,n}config
5a4630aadb9a ftrace: Build with CPPFLAGS to get -Qunused-arguments
Note that this adds new cleanup work to do in that we should adapt the
shared library support we have to what is now upstream.
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Align Kconfig and Kbuild logic to Linux 4.18 release with minimal impact
on files outside of this scope.
Our previous Kconfig sync was done by commit e91610da7c ("kconfig:
re-sync with Linux 4.17-rc4").
A very small number of changes upstream since our sync with v4.17-rc4
that exist in the v4.18 release have already been applied here and have
been omitted from the list in this commit (and are readily available in
our own git history).
The imported Linux commits are:
[From prior to v4.17-rc4]
39a33ff80a25 kbuild: remove cc-option-align
db547ef19064 Kbuild: don't add obj tree in additional includes
b999596b963a Kbuild: don't add ../../ to include path
[From v4.17 to v4.18]
b3aa58d2e85d fixdep: suppress consecutive / from file paths in dependency list files
74656b682902 kbuild: disable new dtc graph and unit-address warnings
74d931716151 genksyms: remove symbol prefix support
e6ecfb45072c kbuild: do not display CHK for filechk
0b669a5076fd kconfig: refactor Qt package checks for building qconf
b464ef583dc7 kconfig: refactor GTK+ package checks for building gconf
1c5af5cf9308 kconfig: refactor ncurses package checks for building mconf and nconf
694c49a7c01c kconfig: drop localization support
96f60dfa5819 trace: Use -mcount-record for dynamic ftrace
bb222ceeb327 kconfig: remove string expansion in file_lookup()
96d8e48da55a kconfig: remove string expansion for mainmenu after yyparse()
5b31a9746756 kconfig: remove sym_expand_string_value()
137c0118a900 kconfig: make default prompt of mainmenu less specific
e298f3b49def kconfig: add built-in function support
2fd5b09c201e kconfig: add 'shell' built-in function
9de071536c87 kconfig: begin PARAM state only when seeing a command keyword
9ced3bddec08 kconfig: support user-defined function and recursively expanded variable
1175c02506ff kconfig: support simply expanded variable
ed2a22f277c6 kconfig: support append assignment operator
82bc8bd82e5c kconfig: expand lefthand side of assignment statement
1d6272e6fe43 kconfig: add 'info', 'warning-if', and 'error-if' built-in functions
a702a6176e2f kconfig: add 'filename' and 'lineno' built-in variables
915f64901eb3 kconfig: error out if a recursive variable references itself
2bece88f89fa kconfig: test: add Kconfig macro language tests
21c54b774744 kconfig: show compiler version text in the top comment
59f7b5847b0c kbuild: $(CHECK) doesnt need NOSTDINC_FLAGS twice
145167650b96 kbuild: add endianness flag to CHEKCFLAGS
1f2f01b122d7 kbuild: add machine size to CHECKFLAGS
d6a0c8a1326b kconfig: Add testconfig into make help output
bb6d83dde191 kbuild: Move last word of nconfig help to the previous line
8593080c0fcf kconfig: fix localmodconfig
ed7d40bc67b8 tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcount
b2d00d7c61c8 kconfig: fix line numbers for if-entries in menu tree
ecd53ac2f2c6 kconfig: handle P_SYMBOL in print_symbol()
73d1c580f92b kconfig: loop boundary condition fix
48f6e3cf5bc6 kbuild: do not drop -I without parameter
bd412d81b7ea kbuild: .PHONY is not a variable, but PHONY is
6916162c7308 kbuild: remove duplicated comments about PHONY
Cc: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
This is U-Boot own code, and no longer used since commit 36dd5f1b8a
("dtc: Switch to building and using our own dtc unless provided").
Prior to that commit, U-Boot relied on an external dtc, so this script
was used to check the dtc version.
Now U-Boot bundles our own dtc in script/dtc/dtc like Linux kernel.
Users are still allowed to pass DTC= option from the command line,
but they are supposed to choose correct version of dtc in this case.
So, we do not check the dtc version any more.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Based on the following Linux commits:
- 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove
.PRECIOUS markers")
- 8e9b61b293d9 ("kbuild: move .SECONDARY special target to
Kbuild.include")
GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.
Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped
A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.
.SECONDARY
Prerequisites of this special target are treated as intermediate
files but are never automatically deleted.
.PRECIOUS
When make is interrupted during execution, it may delete the target
file it is updating if the file was modified since make started.
If you mark the file as precious, make will never delete the file
if interrupted.
Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.
The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.
.SECONDARY with no prerequisites causes all targets to be treated as
secondary. This agrees the policy of Kbuild.
scripts/Kbuild.include seems a suitable place to add it because it is
included from almost all sub-makes.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Linux commit 9c2af1c7377a8a6ef86e5cabf80978f3dbbb25c0
If Make gets a fatal signal while a shell is executing, it may delete
the target file that the recipe was supposed to update. This is needed
to make sure that it is remade from scratch when Make is next run; if
Make is interrupted after the recipe has begun to write the target file,
it results in an incomplete file whose time stamp is newer than that
of the prerequisites files. Make automatically deletes the incomplete
file on interrupt unless the target is marked .PRECIOUS.
The situation is just the same as when the shell fails for some reasons.
Usually when a recipe line fails, if it has changed the target file at
all, the file is corrupted, or at least it is not completely updated.
Yet the file’s time stamp says that it is now up to date, so the next
time Make runs, it will not try to update that file.
However, Make does not cater to delete the incomplete target file in
this case. We need to add .DELETE_ON_ERROR somewhere in the Makefile
to request it.
scripts/Kbuild.include seems a suitable place to add it because it is
included from almost all sub-makes.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
[ commit 9564a8cf422d7b58f6e857e3546d346fa970191e in Linux ]
I tried building using a freshly built Make (4.2.1-69-g8a731d1), but
already the objtool build broke with
orc_dump.c: In function ‘orc_dump’:
orc_dump.c:106:2: error: ‘elf_getshnum’ is deprecated [-Werror=deprecated-declarations]
if (elf_getshdrnum(elf, &nr_sections)) {
Turns out that with that new Make, the backslash was not removed, so cpp
didn't see a #include directive, grep found nothing, and
-DLIBELF_USE_DEPRECATED was wrongly put in CFLAGS.
Now, that new Make behaviour is documented in their NEWS file:
* WARNING: Backward-incompatibility!
Number signs (#) appearing inside a macro reference or function invocation
no longer introduce comments and should not be escaped with backslashes:
thus a call such as:
foo := $(shell echo '#')
is legal. Previously the number sign needed to be escaped, for example:
foo := $(shell echo '\#')
Now this latter will resolve to "\#". If you want to write makefiles
portable to both versions, assign the number sign to a variable:
C := \#
foo := $(shell echo '$C')
This was claimed to be fixed in 3.81, but wasn't, for some reason.
To detect this change search for 'nocomment' in the .FEATURES variable.
This also fixes up the two make-cmd instances to replace # with $(pound)
rather than with \#. There might very well be other places that need
similar fixup in preparation for whatever future Make release contains
the above change, but at least this builds an x86_64 defconfig with the
new make.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197847
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Using the update-dtc-source.sh script from Linux v4.14-rc1 import the
portions of dtc that we require. We bring in update-dtc-source.sh and
scripts/dtc/Makefile from Linux v4.14-rc1. Rework DTC_FLAGS handling to
not require a test.
Signed-off-by: Tom Rini <trini@konsulko.com>
At present we have SPL_ which can be used in Makefiles to select between
normal and SPL CONFIGs like this:
obj-$(CONFIG_$(SPL_)DM) += core/
When TPL is being built, SPL_ has the value 'SPL' which is generally a
good idea since they tend to follow each other. But in extreme situations
we may want to distinugish between SPL and TPL. For example we may not
want to enable CONFIG_DM with TPL.
Add a new SPL_TPL_ variable which is set to either empty (for U-Boot
proper), 'SPL' or 'TPL'. This may prove useful with TPL-specific options.
Signed-off-by: Simon Glass <sjg@chromium.org>
DTC 1.4.2 or later checks DT unit-address without reg property and
vice-versa, and generates lots of warnings. Fixing DT files will
take for a while. Until then, let's turn off the check unless
building with W=*.
Introduce a new helper dtc-option to check if the option is supported
in order to suppress warnings on older versions.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Adapted from:
>From 5631d9c429857194bd55d7bcd8fa5bdd1a9899a3 Mon Sep 17 00:00:00 2001
From: Michal Marek <mmarek@suse.com>
Date: Wed, 19 Aug 2015 17:36:41 +0200
Subject: [PATCH 1/1] kbuild: Fix clang detection
We cannot detect clang before including the arch Makefile, because that
can set the default cross compiler. We also cannot detect clang after
including the arch Makefile, because powerpc wants to know about clang.
Solve this by using an deferred variable. This costs us a few shell
invocations, but this is only a constant number.
Reported-by: Behan Webster <behanw@converseincode.com>
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
in the Linux kernel.
This will allow us to make better decisions about when to run tests
later on for gcc features.
Signed-off-by: Tom Rini <trini@konsulko.com>
Commit e02ee2548a ("kconfig: switch to single .config
configuration") made the configuration itself pretty simple,
instead, we lost the way to systematically enable/disable config
options for each image independently.
Our current strategy is, put entries into Makefile.spl for options
we need separate enabling, or once enable the options globally in
Kconfig and then undef them in Makefile.uncmd_spl if we do not want
to compile the features for SPL at all. Things are getting really
messy. Besides, "ifdef CONFIG_SPL_BUILD" are sprinkled everywhere
in makefiles.
This commit adds a variable to help describe makefile simpler.
$(SPL_) evaluates to "SPL_" during the SPL build, while to an empty
string during building U-boot proper.
So, you can write
obj-$(CONFIG_$(SPL_)FOO) += foo.o
instead of
ifdef CONFIG_SPL_BUILD
obj-$(CONFIG_SPL_FOO) += foo.o
else
obj-$(CONFIG_FOO) += foo.o
endif
If CONFIG_SPL_FOO does not exist in Kconfig, it is equivalent to
ifndef CONFIG_SPL_BUILD
obj-$(CONFIG_SPL_FOO) += foo.o
endif
This is the pattern we often see in our current makefiles.
To take advantage of this macro, we should prefix SPL_ for the SPL
version of the option when we need independent control between
U-boot and SPL. With this naming scheme, I hope our makefiles will
be much simplified.
It means we want to rename existing config options as follows
in the long run:
CONFIG_SPL_SERIAL_SUPPORT -> CONFIG_SPL_SERIAL
CONFIG_SPL_I2C_SUPPORT -> CONFIG_SPL_I2C
CONFIG_SPL_GPIO_SUPPORT -> CONFIG_SPL_GPIO
CONFIG_SPL_SPI_SUPPORT -> CONFIG_SPL_SPI
CONFIG_SPL_DISABLE_OF_CONTROL -> CONFIG_SPL_OF_CONTROL
(inverting the logic)
Then drivers/Makefile would be re-worked as follows:
obj-$(CONFIG_$(SPL_)SERIAL) += serial/
obj-$(CONFIG_$(SPL_)I2C) += i2c/
obj-$(CONFIG_$(SPL_)GPIO) += gpio/
obj-$(CONFIG_$(SPL_)SPI) += spi/
...
Eventually, SPL-specialized entries in Makefile.spl would go away.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Update some build scripts to match Linux 4.1. Commit-based syncing
was done so as not to break U-Boot specific changes.
The previous big sync was from Linux 3.18-rc1 by commit 176d098277
(kbuild: sync misc scripts with Linux 3.18-rc1).
The commits imported from Linux (some with adjustments) are:
[1] commit 9fb5e5372208973984a23ee6f5f025c05d364633
Author: Robert Richter <rrichter@cavium.com>
dts, kbuild: Factor out dtbs install rules to Makefile.dtbinst
[2] commit 371fdc77af44f4cb32475fd499e1d912ccc30890
Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: collect shorthands into scripts/Kbuild.include
[3] commit a29b82326ed4eb5567b03c85b52c6891578d5a03
Author: Michal Marek <mmarek@suse.cz>
kbuild: Remove duplicate $(cmd) definition in Makefile.clean
[4] commit 1846dfbde3e8a53f3673dcb1c1b79fd9b3f8d40d
Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: remove redundant -rR flag of hdr-inst
[5] commit 34948e0bbf98640fc1821751b01d2f0cd17d84d5
Author: Michal Marek <mmarek@suse.cz>
kbuild: Drop support for clean-rule
[6] commit a16c5f99a28c9945165c46da27fff8e6f26f8736
Author: Michal Marek <mmarek@suse.cz>
kbuild: Fix removal of the debian/ directory
[7] commit d0d38cd9e853db11e0242b3df4c9c3c4a663fbb4
Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: use mixed-targets when two or more config targets are given
[8] commit dd33c03b18b3f2db791eb6a17c37d2de66e4de18
Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: fix cc-ifversion macro
[9] commit 665d92e38f65d70796aad2b8e49e42e80815d4a4
Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: do not add $(call ...) to invoke cc-version or cc-fullversion
[10] commit 6dcb4e5edf39e3b65a75ca76f087b2fdbee8a808
Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: allow cc-ifversion to have the argument for false condition
[11] commit c0a80c0c27e5e65b180a25e6c4c2f7ef9e386cd3
Author: Heiko Carstens <heiko.carstens@de.ibm.com>
ftrace: allow architectures to specify ftrace compile options
[12] commit 0b24becc810dc3be6e3f94103a866f214c282394
Author: Andrey Ryabinin <a.ryabinin@samsung.com>
kasan: add kernel address sanitizer infrastructure
[13] commit 4218affdf57f938c04e3a916a9685ee27079f377
Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
kbuild: remove warning about "make depend"
[14] commit 77479b38e2f58890eb221a0418357502a5b41cd6
Author: Nathan Rossi <nathan.rossi@xilinx.com>
kbuild: Create directory for target DTB
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Robert Richter <rrichter@cavium.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Nathan Rossi <nathan.rossi@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This commit imports some updates in misc scripts from Linux 3.18-rc1.
[1] commit cbb4d3e6510b99522719c5ef0 by Horia Geanta
scripts/kernel-doc: handle object-like macros
[2] commit 164f0d2efaaef83 by Michal Marek
kbuild: Fix handling of backslashes in *.cmd files
[3] commit 270a00963cd367214e by Randy Dunlap
scripts/kernel-doc: recognize __meminit
[4] commit a4954fd7724c0f55361eb5 by Masahiro Yamada
kbuild: remove obj-n and lib-n handling
[5] commit 5b2389b45d1a9c12b9f by Masahiro Yamada
kbuild: simplify build, clean, modbuiltin shorthands
Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
By default clang will echo a warning if a warning option is
unknown. Turning warnings into errors when polling for options
also catches such cases and prevents passing arguments to the
compiler which cause warnings.
cc: Masahiro Yamada <yamada.m@jp.panasonic.com>
cc: Tom Rini <trini@ti.com>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
Without this workaround, you will see a lot of ".*.su" files
at the top directory after building with a compiler
which supports "-fstack-usage" option.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Now we are ready to switch over to real Kbuild.
This commit disables temporary scripts:
scripts/{Makefile.build.tmp, Makefile.host.tmp}
and enables real Kbuild scripts:
scripts/{Makefile.build,Makefile.host,Makefile.lib}.
This switch is triggered by the line in scripts/Kbuild.include
-build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build.tmp obj
+build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
We need to adjust some build scripts for U-Boot.
But smaller amount of modification is preferable.
Additionally, we need to fix compiler flags which are
locally added or removed.
In Kbuild, it is not allowed to change CFLAGS locally.
Instead, ccflags-y, asflags-y, cppflags-y,
CFLAGS_$(basetarget).o, CFLAGS_REMOVE_$(basetarget).o
are prepared for that purpose.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
Some build scripts including scripts/Makefile.build
will be imported from Linux Kernel in the next commit.
We need to adjust them for U-Boot in the following commits.
To make it easier for reviewers to track the modification,
this commit renames scripts/Makefile.build to
scripts/Makefile.build.tmp beforehand.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
This commit changes the working directory
where the build process occurs.
Before this commit, build process occurred under the source
tree for both in-tree and out-of-tree build.
That's why we needed to add $(obj) prefix to all generated
files in makefiles like follows:
$(obj)u-boot.bin: $(obj)u-boot
Here, $(obj) is empty for in-tree build, whereas it points
to the output directory for out-of-tree build.
And our old build system changes the current working directory
with "make -C <sub-dir>" syntax when descending into the
sub-directories.
On the other hand, Kbuild uses a different idea
to handle out-of-tree build and directory descending.
The build process of Kbuild always occurs under the output tree.
When "O=dir/to/store/output/files" is given, the build system
changes the current working directory to that directory and
restarts the make.
Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=<sub-dir>"
syntax for descending into sub-directories.
(We can write it like "make $(obj)=<sub-dir>" with a shorthand.)
This means the current working directory is always the top
of the output directory.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
This commit adjusts some files to use Kbuild.include.
- Use cc-option defined in Kbuild.include
(Delete cc-option in config.mk)
- Use cc-version defined in
(Delete cc-version in config.mk)
- Move binutils-version and dtc-version to Kbuild.include
by analogy to cc-version
This commit also adds srctree (same as SRCTREE)
to use Kbuild scripts.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
