Re: [gentoo-embedded] crossdev, alternate root, and build dependencies

[Joakim Tjernlund]

"Dustin C. Hatch" <admiralnemo@×××××.com> wrote on 2012/12/13 00:43:51:
>
> (Originally posted on gentoo-user, but may be more appropriate here)
>
> I am trying to understand and use crossdev to build Gentoo for my
> Raspberry Pi, and I have a couple of questions. I was able to
> successfully build a toolchain::
>
>      crossdev -S -t armv6j-hardfloat-linux-gnueabi
>
> This correctly installed binutils, gcc, glibc, and linux-headers::
>
>      equery list cross-armv6j-hardfloat-linux-gnueabi/*
>       * Searching for * in cross-armv6j-hardfloat-linux-gnueabi ...
>      [I-O] [  ] cross-armv6j-hardfloat-linux-gnueabi/binutils-2.22-r1:0
>      [I-O] [  ] cross-armv6j-hardfloat-linux-gnueabi/gcc-4.5.4:4.5
>      [I-O] [  ] cross-armv6j-hardfloat-linux-gnueabi/glibc-2.15-r3:2.2
>      [I-O] [  ] cross-armv6j-hardfloat-linux-gnueabi/linux-headers-3.6:0
>
> I then copied the configuration from
> /usr/armv6j-hardfloat-linux-gnueabi/etc/portage to an alternate
> location, so I could modify it without impacting the crossdev toolchain.

> Next, I started to emerge some ebuilds into a staging directory using
> the following commands::
>
>      export CBUILD=$(portageq envvar CHOST)
>      export PORTAGE_CONFIGROOT=/home/dustin/rpi-build/configroot
>      export ROOT=/home/dustin/rpi-build/buildroot/
>      export PORTAGE_TMPDIR=/home/dusitn/rpi-build/tmp
>      emerge --nodeps baselayout
>      emerge --onlydeps baselayout
>
> The first pass completed successfully, but the second failed to build
> psmisc::
>
>      checking for tgetent in -ltinfo... no
>      checking for tgetent in -lncurses... no
>      checking for tgetent in -ltermcap... no
>      configure: error: Cannot find tinfo, ncurses or termcap libraries
>
> config.log shows this::
>
>      configure:3970: checking for tgetent in -lncurses
>      configure:3995: armv6j-hardfloat-linux-gnueabi-gcc -o conftest -O4
>      -pipe -mfpu=vfp -mfloat-abi=hard -march=armv6zk -mtune=arm1176jzf-s
>      -fomit-frame-pointer   conftest.c -lncurses   >&5
>      /usr/libexec/gcc/armv6j-hardfloat-linux-gnueabi/ld: cannot find
>      -lncurses
>      collect2: ld returned 1 exit status
>      configure:3995: $? = 1
>
> ncurses did get installed in the alternate root::
>
>      ls -1 ${ROOT}lib/libncurses*
>      /home/dustin/rpi-build/buildroot/lib/libncurses.so.5
>      /home/dustin/rpi-build/buildroot/lib/libncurses.so.5.9
>      /home/dustin/rpi-build/buildroot/lib/libncursesw.so.5
>      /home/dustin/rpi-build/buildroot/lib/libncursesw.so.5.9
>
> Now, I've found that if I install ncurses in /usr/${CHOST} instead of
> ${ROOT}, psmisc will build successfully. I am thus confused on where
> things are supposed to be built. The Cross Development Guide says not to

> install pieces of the toolchain in /usr/${CHOST}, but some ebuilds, like

> openrc, have explicit RDEPENDs on them, so emerge pulls them in. I'm not

> sure how to resolve this seeming catch-22 where I can't install runtime
> dependencies in /usr/${CHOST}, but I also can't install build
> dependencies in in ${ROOT}.
>
> I am hoping to have this process scriptable, so my current method of
> just installing missing build dependencies in /usr/${CHOST} after
> something fails won't work. Any pointers would be appreciated.

This is the way crossdev works, I too wish one could avoid doing an extra 
build into /usr/${CHOST}
One thing to try is adding --sysroot=${ROOT}(or something near that) to 
your CFLAGS/LDFLAGS
Please let me know how that work out as I will be going down a similar 
route in the foreseeable future.

 Jocke