[Buildroot] Problems building for ucLinux/ARM with elf2flt enabled

[Anna Fischer (novero/Bochum)]

> Subject: Re: [Buildroot] Problems building for ucLinux/ARM with elf2flt
> enabled
> 
> On Wed, Jul 24, 2013 at 1:39 PM, Anna Fischer (novero/Bochum)
> <Anna.Fischer at novero.com> wrote:
> >> Subject: Re: [Buildroot] Problems building for ucLinux/ARM with
> >> elf2flt enabled
> >>
> >> Hi Anna,
> >>
> >> On Wed, Jul 24, 2013 at 12:02 PM, Anna Fischer (novero/Bochum)
> >> <Anna.Fischer at novero.com> wrote:
> >> > I'm trying to build a ucLinux system for an ARM platform (no-MMU),
> >> but when trying to enabled elf2flt in the menuconfig I get the
> >> following error:
> >> >
> >> > /home/buildroot-2013.05/output/build/host-binutils-
> >> 2.21.1/bfd/libbfd.a(compress.o): In function
> >> `bfd_compress_section_contents':
> >> > compress.c:(.text+0x25): undefined reference to `compressBound'
> >> > /home//buildroot-2013.05/output/build/host-binutils-
> >> 2.21.1/bfd/libbfd.a(compress.o): In function
> >> `bfd_get_full_section_contents':
> >> > compress.c:(.text+0x226): undefined reference to `inflateEnd'
> >> > compress.c:(.text+0x37a): undefined reference to `inflateInit_'
> >> > compress.c:(.text+0x3b0): undefined reference to `inflate'
> >> > compress.c:(.text+0x3bf): undefined reference to `inflateReset'
> >> > collect2: ld returned 1 exit status
> >> > make[1]: *** [elf2flt] Error 1
> >> > make[1]: Leaving directory `/home/buildroot-
> >> 2013.05/output/toolchain/elf2flt'
> >> > make: ***
> >> > [/home/buildroot-2013.05/output/toolchain/elf2flt/elf2flt]
> >> > Error 2
> >> >
> >> > It seems like it is missing libz? But I don't quite understand
> why,
> >> because I definitely have it installed on the system. Anyone ever
> >> seen this before?
> >> >
> >> > I'm using the buildroot internal toolchain, uClibc-0.9.33.2, gcc-
> >> 4.7.3, linux-3.8, and this is buildroot-2013.05. I have attached my
> >> .config as well. My build host is Ubuntu 64-bit.
> >>
> >> Do you have the -dev package of zlib? Also for 64-bit?
> >>
> >> On a CentOS system, I have seen a problem with the static version of
> >> zlib missing, when building a static toolchain with crosstool-ng. On
> >> CentOS, the static version (libz.a) is distributed as a separate
> >> package. I don't know if this is the case on your system.
> >
> > libz.a and libz.so are installed in output/host/usr/lib in the
> buildroot system, so apart from the fact that I have it installed as
> part of my Ubuntu distribution (yes, I have the -dev package
> installed), it is present in the buildroot output directory. The
> elf2flt Makefile also references this folder in LDFLAGS. It is not
> clear to me though if the problem is in elf2flt or in the binutils
> itself under build/host-binutils-2.21.1/bfd (as referenced by the error
> message I printed out above)?
> 
> Where exactly can you find libz in output/ ?
> Since the error is in a host package, there should be such files in
> output/host/ Any libz files in output/staging are irrelevant, as these
> are for the target, not for the host.
> 
> If there is no libz in output/host, there may be a missing dependency
> to host-zlib in binutils. You could verify this by running 'make host-
> zlib' manually first, and then retrying the binutils build.

I have fixed the problem now by adding the -lz to the end of the gcc command in the elf2flt Makefile. 
Now the whole system builds without errors.

However, in the target folder I'm still getting ELF files compiled, not FLAT format binaries. Is there any way I can tell the build system to change the binary format to FLAT by using the elf2flt tool at the end of each build process for binaries (or by adding -elf2flt to the build command)? I was hoping that by enabling elf2flt support it would do that automatically for target binaries.

Any pointers would be really appreciated.