GCC7 ARMv7-a compilation error in standard headers - c++

I am trying to compile my C++1z application for the ARMv7-a architecture using GCC7. I tested and have the application working in Ubuntu 16.04 (x86_64), but when I try compiling it on the ARM device (Ubuntu 14.04) I end up with compilation errors in the standard headers. One example of the errors is:
In file included from /usr/include/c++/7/bits/ios_base.h:46:0,
from /usr/include/c++/7/ios:42,
from /usr/include/c++/7/istream:38,
from /usr/include/c++/7/sstream:38,
from /usr/include/c++/7/complex:45,
from /home/ubuntu/work/git_rep/surrogate/external/opencv/modules/core/include/opencv2/core/cvstd.inl.hpp:47,
from /home/ubuntu/work/git_rep/surrogate/external/opencv/modules/core/include/opencv2/core.hpp:3217,
from /home/ubuntu/work/git_rep/surrogate/external/opencv/modules/videoio/include/opencv2/videoio.hpp:46,
from /home/ubuntu/work/git_rep/surrogate/service/streaming/video/stereo_camera_stream.h:5,
from /home/ubuntu/work/git_rep/surrogate/service/streaming/video/stereo_camera_stream.cc:1:
/usr/include/c++/7/system_error: At global scope:
/usr/include/c++/7/system_error:151:31: error: ‘error_category’ does not name a type; did you mean ‘error_code’?
error_code(int __v, const error_category& __cat) noexcept
^~~~~~~~~~~~~~
error_code
/usr/include/c++/7/system_error:160:27: error: ‘error_category’ does not name a type; did you mean ‘error_code’?
assign(int __v, const error_category& __cat) noexcept
^~~~~~~~~~~~~~
error_code
/usr/include/c++/7/system_error:180:11: error: ‘error_category’ does not name a type; did you mean ‘error_code’?
const error_category&
^~~~~~~~~~~~~~
error_code
/usr/include/c++/7/system_error:199:11: error: ‘error_category’ does not name a type; did you mean ‘error_code’?
const error_category* _M_cat;
^~~~~~~~~~~~~~
error_code
/usr/include/c++/7/system_error: In constructor ‘std::error_code::error_code()’:
/usr/include/c++/7/system_error:149:20: error: class ‘std::error_code’ does not have any field named ‘_M_cat’
: _M_value(0), _M_cat(&system_category()) { }
^~~~~~
/usr/include/c++/7/system_error:149:28: error: ‘system_category’ was not declared in this scope
: _M_value(0), _M_cat(&system_category()) { }
^~~~~~~~~~~~~~~
/usr/include/c++/7/system_error:149:28: note: suggested alternative:
/usr/include/c++/7/system_error:134:40: note: ‘std::_V2::system_category’
_GLIBCXX_CONST const error_category& system_category() noexcept;
^~~~~~~~~~~~~~~
The compiler recommends replacing std::system_category with std::_V2::system_category, as though there would be an error in the standard header. I compared the header against the header I used when compiling my application for a x86_64 environment, and they seem the same, which leaves me guessing as to why the compilation targeting ARMv7-a is failing.
I am using CMake to build the source code, so - to the best of my knowledge - there should be no other differences in configuration apart from system specific options. I compared the configurations of the two compilers I used by running gcc -v. They are as follows:
GCC7 (x86_64)
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 7.2.0-1ubuntu1~16.04' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 7.2.0 (Ubuntu 7.2.0-1ubuntu1~16.04)
GCC7 (ARMv7-a)
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/7/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 7.2.0-1ubuntu1~14.04' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=arm-linux-gnueabihf- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=gcc4-compatible --disable-libstdcxx-dual-abi --enable-gnu-unique-object --disable-libitm --disable-libquadmath --enable-plugin --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --enable-multilib --disable-sjlj-exceptions --with-arch=armv7-a --with-fpu=vfpv3-d16 --with-float=hard --disable-werror --enable-multilib --enable-checking=release --build=arm-linux-gnueabihf --host=arm-linux-gnueabihf --target=arm-linux-gnueabihf
Thread model: posix
gcc version 7.2.0 (Ubuntu/Linaro 7.2.0-1ubuntu1~14.04)
One of the differences in the configuration that stood out for me is --with-default-libstdcxx-abi, which is set to gcc4-compatible for ARMv7-a and new for x86_64, as it influences the implementation of the error_category class.
I am not sure how it could cause the compile error I am seeing though, so this is where I turn to you. What could be the cause and a possible fix for the compile error I described?
Edit
After splitting a header file included by the affected file into two separate headers and - resultingly - compilation units, the compile errors turned into linker errors, all similar to the following:
../../lib/libservice.a(duplicate_camera_stream.cc.o):duplicate_camera_stream.cc:(.text+0x12c4): first defined here
../../lib/libservice.a(simulated_video_stream.cc.o): In function `std::make_error_code(std::io_errc)':
simulated_video_stream.cc:(.text+0x100d8): undefined reference to `std::iostream_category()'
../../lib/libservice.a(simulated_video_stream.cc.o): In function `std::make_error_condition(std::io_errc)':
simulated_video_stream.cc:(.text+0x10110): undefined reference to `std::iostream_category()'
This led me to thinking that there might be an incompatibility with the C++ standard of the OpenCV libraries that I am statically linking against.
Solution
After compiling the source code of OpenCV using the same C++ standard as the rest of my code, the linking errors dissapeared, and the build was successfull.
Could it be that by including OpenCV headers in - and linking libraries of an older C++ standard against - an application with a different C++ standard; linker and/or compile errors could occur?

Related

Installing g++ = 7.5.0 with support for Cilk Plus

I want to use https://github.com/yushangdi/parChain however I can't fullfil requirement:
Compiler:
g++ = 7.5.0 with support for Cilk Plus
I have a problem with installing GCC with Cilk. I try to follow some tutorials from the websites but any of them doesn't work correctly. Unfortunately, the Cilk project was transformed into Intel's project many documentation URLs don't work anymore. I got following error after run $./pc_exp.sh
In file included from sequence.h:27:0,
from framework.C:1:
parallel.h:25:10: fatal error: cilk/cilk.h: Not found
#include <cilk/cilk.h>
^~~~~~~~~~~~~
compilation terminated.
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 7.5.0-6ubuntu2' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 7.5.0 (Ubuntu 7.5.0-6ubuntu2)
$ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 7.5.0-6ubuntu2' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 7.5.0 (Ubuntu 7.5.0-6ubuntu2)
I need to run this on both: Ubuntu 20.04 and Centos 7. I'm not Linux/c++ experienced user. Can you help me with some tutorials?
I recommend you consider OpenCilk, an active open source project that picks up where Cilk Plus left off. OpenCilk 2.0 was released just a couple weeks ago, and it definitely supports Ubuntu 20.04. (Not sure about Centos.) Please see https://www.opencilk.org for tutorials on programming with Cilk (which is based on LLVM btw).

C++11 used by default? [duplicate]

This question already has answers here:
How do I check for C++11 support?
(9 answers)
Closed 4 years ago.
How can I know whether c++11 is used by default in my g++ compiler? My OS is ubuntu 18.04.1.
zell#ubuntu:~$ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 7.3.0-27ubuntu1~18.04' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 7.3.0 (Ubuntu 7.3.0-27ubuntu1~18.04)
It is--one resource out there is gcc/g++ web page on C++ status and standards:
g++ 4.8.1 and above support C++11 and I recall g++-7 having it as default
and I had seen that stated on that page before but I am not seeing it now...
g++ 6.1 and above default to C++14 as per the page
You can of course switch and make explicit choices with the usual -std=... flag.
My way (no compiler dependand): compile and run the following program
#include <iostream>
int main()
{ std::cout << __cplusplus << std::endl; }
You'll get (supposing a standard compliant compiler)
"199711", for C++98
"201103", for C++11
"201402", for C++14
"201703", for C++17

Cannot Build Boost 1.47.0 IOStreams on Ubuntu

I am working on a legacy project for my company that requires me to use a specific version of boost and that version is 1.47.0. I have downloaded and run:
./b2 --toolset=gcc variant=debug
and it compiled the majority of the static libraries I needed with the exception of a few. One being libboost_iostreams. I did some research and found that it appeared i was missing some dependencies.
whereis bzip2
bzip2: /bin/bzip2 /usr/share/man/man1/bzip2.1.gz
whereis zlib
zlib: /usr/include/zlib.h /usr/share/man/man3/zlib.3.gz
However when I attempt to run:
./b2 --with-iostreams -s BZIP2_SOURCE=/bin -s ZLIB_SOURCE=/usr/include
I am getting the following error:
Building the Boost C++ Libraries.
error: Unable to find file or target named
error: '/bin/libbz2.def'
error: referred from project at
error: 'libs/iostreams/build'
Update:
Linux Version: 16.04
Gcc Version Info:
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/5/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 5.4.0-
6ubuntu1~16.04.9' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs --
enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --
program-suffix=-5 --enable-shared --enable-linker-build-id --
libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --
libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-
libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-
plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --
enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-amd64/jre --
enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-amd64 --
with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-amd64 --with-arch-
directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-
objc-gc --enable-multiarch --disable-werror --with-arch-32=i686 --with-
abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-
tune=generic --enable-checking=release --build=x86_64-linux-gnu --
host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.9)

Prefer sysroot headers over headers in the toolchain using gcc

I'm trying to cross-compile a simple code snippet
1 #include <sys/socket.h>
2 #include <stdio.h>
3
4 int main()
5 {
6 printf("%d\n", SOL_NETLINK);
7 return 0;
8 }
with arm-linux-gnueabihf-g++ (from Ubuntu) against Raspbian sysroot with --sysroot switch set to $SYSROOT
The compilation fails with this error:
test.cpp:6:20: error: ‘SOL_NETLINK’ was not declared in this scope
Even though $SYSROOT/usr/include/arm-linux-gnueabihf/bits/socket.h contains
the needed define.
So I figured that toolchain contains the mentioned header as well and it's included first. The latter header somehow doesn't have this SOL_NETLINK define. So I need a way to tell the compiler to prefer the toolchain's headers to sysroot's ones.
> arm-linux-gnueabihf-g++ -v
Using built-in specs.
COLLECT_GCC=arm-linux-gnueabihf-g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/arm-linux-gnueabihf/5/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs --enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-5 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libitm --disable-libquadmath --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-armhf-cross/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-armhf-cross --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-armhf-cross --with-arch-directory=arm --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libgcj --enable-objc-gc --enable-multiarch --enable-multilib --disable-sjlj-exceptions --with-arch=armv7-a --with-fpu=vfpv3-d16 --with-float=hard --with-mode=thumb --disable-werror --enable-multilib --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=arm-linux-gnueabihf --program-prefix=arm-linux-gnueabihf- --includedir=/usr/arm-linux-gnueabihf/include
Thread model: posix
gcc version 5.4.0 20160609 (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.4)
#include <sys/socket.h> will include a file which is under the folder {include path}/sys/socket.h.
Include path can be any folder that you add with various options like gcc -I or --includedir. In addition there are some default include path, which you should be able to see with gcc -xc++ -E -v -.
Using gcc "-I" option will put the include path to search first, before any of the default include paths.
Now, this should give you enough information to understand that the include you give can't point to the file $SYSROOT/usr/include/arm-linux-gnueabihf/bits/socket.h as it isn't end with {include path}/sys/socket.h
Use -isystem flag with $SYSROOT/usr/include/arm-linux-gnueabihf
Albeit GCC can resolve triple (arm-linux-gnueabihf part) in the path, but it won't do so with --sysroot option.

gdb error message: DW_OP_reg, DW_OP_piece, and DW_OP_bit_piece

I'm debugging somebody else's Qt program and ran into the following error message which I don't understand:
DWARF-2 expression error: DW_OP_reg operations must be used either alone or in
conjuction with DW_OP_piece or DW_OP_bit_piece.
I'm not sure what that means and Google isn't of much help.
Here's the context - sLocation is a QString that was declared a few lines earlier. However, it was created from functions which were inlined, so I'm not sure of its value and am attempting to check before being appended to:
(gdb) printqstring suffix
(QString)0xffffbd80: "sorted"
(gdb) next
1241 sLocation += suffix;
(gdb) printqstring sLocation
Can't take address of "sLocation" which isn't an lvalue.
(gdb) info local
sLocation = <error reading variable sLocation (DWARF-2 expression error:
DW_OP_reg operations must be used either alone or in conjuction with
DW_OP_piece or DW_OP_bit_piece.)>
Could somebody please explain what that error message means or what could cause it?
The error message means that GDB is reading DWARF2 debug info from the executable, and is rejecting that info as invalid (not following the DWARF2 standard).
The invalid info is likely due to a bug in GCC, fixed in SVN revision 147187:
2009-05-06 Jakub Jelinek <jakub#redhat.com>
* dwarf2out.c (new_reg_loc_descr): Don't ever create DW_OP_regX.
(one_reg_loc_descriptor): Create DW_OP_regX here instead of calling
new_reg_loc_descr.
(loc_by_reference): If loc is DW_OP_regX, change it into DW_OP_bregX 0
instead of appending DW_OP_deref*.
I got the same problem running a Ubuntu 10.10 64bit. However, the same code on a 10.04 LTS 32bit works perfectly.
Here is the version output of both setups
Ubuntu 10.10:
$ gcc -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.4.4-14ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.4 --enable-shared --enable-multiarch --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.4 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5)
GCC on 10.04 LTS:
$ gcc -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.4.3-4ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared --enable-multiarch --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-plugin --enable-objc-gc --enable-targets=all --disable-werror --with-arch-32=i486 --with-tune=generic --enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnu
Thread model: posix
gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5
Cheers,
Andre