sandbox: support forcing 32-bit x86 ...

If gcc supports multiple architectures, barebox uses only the default
when compiling for ARCH=sandbox, this is e.g. the case with compilers
that generate both 32- and 64-bit x86 executables.

There can be good reasons to force 32-bit though, e.g. to reduce memory
consumption while fuzzing or to temporarily avoid 32-to-64-bit warnings,
while running the static analyzer. Add an option for this.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch: remove KBUILD_SRC checks from arch Makefile ...

You can always add $(srctree)/ to the mach include path.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

kbuild: prefix compiler flag variables with KBUILD_ ...

In old days, Linux also used to use well-known variables such CFLAGS,
CPPFLAGS, etc.

They were prefixed with KBUILD_ presumably for preventing users from
overriding them accidentally.

Rename as follows:
  CFLAGS          ->  KBUILD_CFLAGS
  AFLAGS          ->  KBUILD_AFLAGS
  CPPFLAGS        ->  KBUILD_CPPFLAGS
  LDFLAGS         ->  KBUILD_LDFLAGS
  HOSTCFLAGS      ->  KBUILD_HOSTCFLAGS
  HOSTCXXFLAGS    ->  KBUILD_HOSTCXXFLAGS
  HOSTLDFLAGS     ->  KBUILD_HOSTLDFLAGS
  HOST_LOADLIBES  ->  KBUILD_HOSTLDLIBS

HOSTCFLAGS, HOSTCXXFLAGS, HOSTLDFLAGS, HOSTLDLIBS are re-used to allow
users to pass-in additional flags to the host compiler.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

sandbox: add gpio support with libftdi1 ...

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

sandbox: get malloc_size from .config ...

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

sandbox: add sdl video support ...

This will allow speed up the dev on framebuffer.

By default the resolution is VGA but this can be changed via cmdline.

We use a pthread to Flip the screen every 100ms as we can not detect when
barebox update it as barebox simpliy write in a buffer.

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>

[SANDBOX] Move include/asm-sandbox/arch-* to arch/sandbox/*/include/mach ...

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

Sandbox: Fix make system ...

Sandbox compilation failed with:

gcc -Wp,-MD,arch/sandbox/lib/.tap.o.d  -nostdinc -isystem /usr/lib/gcc/x86_64-linux-gnu/4.3.1/include -I/usr/include -Iinclude -P -Wall    -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(tap)"  -D"KBUILD_MODNAME=KBUILD_STR(tap)" -c -o arch/sandbox/lib/tap.o arch/sandbox/lib/tap.c
In file included from /usr/include/bits/socket.h:32,
                 from /usr/include/sys/socket.h:36,
                 from arch/sandbox/lib/tap.c:29:
/usr/include/limits.h:125:26: error: limits.h: No such file or directory

/usr/include/limits.h uses the next_include directive
This was because of the -nostdinc

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