kbuild: handle multi-objs dependency appropriately ...

The comment in scripts/Makefile.build says as follows:

  We would rather have a list of rules like
        foo.o: $(foo-objs)
  but that's not so easy, so we rather make all composite objects depend
  on the set of all their parts

This commit makes it possible!

For example, assume a Makefile like this

  obj-m = foo.o bar.o
  foo-objs := foo1.o foo2.o
  bar-objs := bar1.o bar2.o

Without this patch, foo.o depends on all of
foo1.o foo2.o bar1.o bar2.o.
It looks funny that foo.o is regenerated when bar1.c is updated.

Now we can handle the dependency of foo.o and bar.o separately.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

pbl: Fix typo in make causing pbl files to be rebuilt ...

We had pbl_cc__o_c instead of pbl_cc_o_c. This caused all pbl object
files to be rebuilt everytime due to missing .cmd file.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

pbl: Add missing FORCE ...

Otherwise the pbl files do not get rebuilt when the CFLAGS change.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kbuild: allow to have custom cppflags for pbl ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

kbuild: add pre-bootloader (pbl) target ...

This will allow to link compiled object to the built-in-pbl.o across the source
tree that will be finally link to the pbl.

Now we compile the source %.c in pbl-%.o and provide -D__PBL__
so we can known in the source when it's compile for barebox or the pbl.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

kbuild: Init all relevant variables used in kbuild files ...

import from linux 3.5-rc5

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Only pass -P to cpp when generating ld scripts ...

When building sandbox with ccache, one would hit warnings such as:
    warning: 'struct mmsghdr' declared inside parameter list
on random files; a way to reproduce this issue is to build a simple
file doing just:
    #include <sys/socket.h>

    int main(void) {
        return 0;
    }

    gcc -Wall -P -c -o foo foo.c

But actually the -P flag is only useful when generating non-C files,
such as linker scripts in the case of barebox.  Removing the -P flag
from all the gcc invocations, except when generating .lds files makes
the warning go away.  It turns out that this is what
linux/scripts/Makefile.build also does nowadays.

Signed-off-by: Loïc Minier <loic.minier@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

svn_rev_008 ...

add missing Kconfig