[PATCH] Enable unwind info in libc-start.c and backtrace.c

[Joseph Myers]

On Thu, 14 Sep 2017, Wilco Dijkstra wrote:

> H.J. Lu wrote:
> 
> > # CC="gcc -m32 -march=i686" CXX="g++ -m32 -march=i686"
> > /export/gnu/import/git/sources/glibc/configure --prefix=/usr
> > --target=i686-linux --build=i686-linux --host=i686-linux
> > --enable-hardcoded-path-in-tests
> >
> > to configure glibc for i686 on Linux/x86-64.  It works fine.
> 
> Doing it exactly like that I get:
> 
> /work/install/binutils_x64/x86_64-linux-gnu/bin/ld: skipping incompatible /work/install/gcc_x64/lib/gcc/x86_64-linux-gnu/8.0.0/libgcc.a when searching for -lgcc
> /work/install/binutils_x64/x86_64-linux-gnu/bin/ld: cannot find -lgcc
> 
> So it doesn't seem to be able to find a 32-bit libgcc although that GCC
> supports -m32...

That suggests you have a --disable-multilib compiler.

You can use build-many-glibcs.py to build an x86_64 compiler that supports 
all of -m64, -m32, -mx32 (build-many-glibcs.py <dir> checkout; 
build-many-glibcs.py <dir> host-libraries; build-many-glibcs.py <dir> 
compilers x86_64-linux-gnu).  Having got that compiler (in 
<dir>/install/compilers/x86_64-linux-gnu) you can then use it for building 
/ testing glibc manually (including running execution tests in such a 
build - make sure to copy libstdc++ and libgcc_s shared libraries from the 
right multilib to the build directory before running make check) if you 
want.

-- 
Joseph S. Myers
joseph@codesourcery.com