"Incorrect selection of the C library" with Emdebian toolchain

Hi. I'm having a problem similar to one reported earlier this year (see
http://goo.gl/lBYtC), namely: SYSROOT_DIR is being computed incorrectly for my external toolchain. I'm trying to use Emdebian's ARM cross toolchain, which I installed in my Ubuntu 12.04 VM using:

sudo apt-get install gcc-4.6-arm-linux-gnueabi

This puts arm-linux-gnueabi-gcc-4.6 in /usr/bin, and the dependent package binutils-arm-linux-gnueabi adds things like arm-linux-gnueabi-ar, arm-linux-gnueabi-as, etc in the same location. However, the latter package also drops a bunch of files in /usr/arm-linux-gnueabi:

/usr/arm-linux-gnueabi

|-- bin
|   |-- ar
|   |-- as
|   |-- ld
|   |-- ld.bfd
|   |-- ld.gold
|   |-- nm
|   |-- objcopy
|   |-- objdump
|   |-- ranlib
|   `-- strip
|-- include
|   |-- aio.h
|   |-- aliases.h
|   <--SNIP!-->
|   |-- wait.h
|   |-- wchar.h
|   |-- wctype.h
|   |-- wordexp.h
|   |-- xen
|   `-- xlocale.h
`-- lib
     |-- crt1.o
     |-- crti.o
     |-- crtn.o
     |-- gcrt1.o
     |-- ld-2.15.so
     |-- ld-linux.so.3 -> ld-2.15.so
     |-- libanl-2.15.so
     <--SNIP--!>
     |-- libstdc++.so.6 -> libstdc++.so.6.0.16
     |-- libstdc++.so.6.0.16
     |-- libthread_db-1.0.so
     |-- libthread_db.so -> libthread_db.so.1
     |-- libthread_db.so.1 -> libthread_db-1.0.so
     |-- libutil-2.15.so
     |-- libutil.a
     |-- libutil.so -> libutil.so.1
     |-- libutil.so.1 -> libutil-2.15.so
     |-- Mcrt1.o
     `-- Scrt1.o

So, as near as I can tell, SYSROOT_DIR should be /usr/arm-linux-gnueabi for this toolchain. The following sed command in ext-tool.mk (~ line
311) is the problem:

SYSROOT_DIR=`echo $${LIBC_A_LOCATION} | sed -r -e
's:usr/lib(64)?/(.*/)?libc\.a::'` ; \

When the above is executed, LIBC_A_LOCATION has the value "/usr/arm-linux-gnueabi/lib/libc.a" so the regex doesn't match anything, and I get the error "Incorrect selection of the C library".

For now, I've temporarily hacked ext-tool.mk to hard-code SYSROOT_DIR to '/usr/arm/arm-linux-gnueabi', which seems to work. Just figured I should tell some folks who may be able to implement a 'real' fix... :-}

Hello,

Le Wed, 22 Aug 2012 20:03:56 -0400,
Evade Flow <[email protected]> a ?crit :

Normally, toolchains installed system-wide in /usr are not usable because their sysroot is mixed with tons of stuff. However, in this case, it sounds like the Emdebian toolchain sysroot
in /usr/arm-linux-gnueabi is clean and may be used by Buildroot. If you can't cook a patch to fix this, I'll try to find some time to do it, but I don't know when.

Best regards,

Thomas

Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

I'll try to put together a patch if the Emdebian toolchain does, in fact, work. (I'm still doing a few sit-ups to verify this...)

I guess I'm not going to use Emdebian, afterall. :-/ I'm attempting to use buildroot, with an external toolchain, just to build a few libraries (glib, libdbus-1, libcap) so I can run some diagnostics on an ARM system. Specifically, I'd like to cross-compile bustle-pcap (see
http://www.willthompson.co.uk/bustle/) and run it on a target device at work to see what the various apps are saying to each other over D-Bus. I don't (yet) need to build a toolchain or root fs, I'm just looking for an easy way to cross-compile glib & friends.

When I try to do this using buildroot + Emdebian (with the hard-coded SYSROOT_DIR 'fix' I mentioned previously), it gets quite far into the build, but then dbus-glib blows up with the errors show below. If I attempt the same thing using buildroot + 'Sourcery CodeBench ARM 2011.09', it works fine.

It's frustrating that Emdebian *almost* works. I can't tell whether this problem is the tip of a very large iceberg, or something that merely requires a few minor patches to fix. Any recommendations about how to fix the errors below? Or is it unlikely to be worth the effort? (I have no need to use Emdebian; I only chose it because I've used it in the past and I'm somewhat familiar with it.)

----------

make[4]: Entering directory `/home/evadeflow/projects/buildroot-2012.05/output/build/dbus-glib-0.98/dbus'

   CC     dbus-glib.lo
   CC     dbus-gmain.lo
   CCLD   libdbus-glib-1.la
   CCLD   dbus-binding-tool

/usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld:
warning: libffi.so.6, needed by /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so, not found (try using -rpath or -rpath-link) /usr/lib/gcc/arm-linux-gnueabi/4.6/../../../../arm-linux-gnueabi/bin/ld:
warning: libz.so.1, needed by /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so, not found (try using -rpath or -rpath-link) /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_void' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_double' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_prep_cif' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `inflate' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `deflateSetHeader at ZLIB_1.2.2' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_sint32' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `deflateReset' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `deflate' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_float' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_uint64' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_sint64' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `deflateInit2_' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `inflateGetHeader at ZLIB_1.2.2' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `deflateInit_' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_pointer' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_type_uint32' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `inflateEnd' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `deflateEnd' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `inflateInit_' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgobject-2.0.so:
undefined reference to `ffi_call' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `inflateInit2_' /home/evadeflow/projects/buildroot-2012.05/output/host/usr/arm-unknown-linux-gnueabi/sysroot/usr/lib/../lib/libgio-2.0.so:
undefined reference to `inflateReset'
collect2: ld returned 1 exit status
make[4]: *** [dbus-binding-tool] Error 1
make[4]: Leaving directory
`/home/evadeflow/projects/buildroot-2012.05/output/build/dbus-glib-0.98/dbus'
make[3]: *** [all-recursive] Error 1
make[3]: Leaving directory
`/home/evadeflow/projects/buildroot-2012.05/output/build/dbus-glib-0.98/dbus'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory
`/home/evadeflow/projects/buildroot-2012.05/output/build/dbus-glib-0.98'
make[1]: *** [all] Error 2
make[1]: Leaving directory
`/home/evadeflow/projects/buildroot-2012.05/output/build/dbus-glib-0.98'
make: ***
[/home/evadeflow/projects/buildroot-2012.05/output/build/dbus-glib-0.98/.stamp_built]
Error 2