State of multilib development

[Hans de Goede]

Hi all,

Yesterday I tried to build i386 rpms on my x86_64 using the new
multilib-devel packages instead of resorting to an i386 chroot.

Although we have come a long way to making this possible there are still
a few issues which makes doing this very hard:

1) gcc ignores setarch
======================

"gcc -o hello helloworld.c", creates an x86_64 elf file on my x86_64
system as expected however, "setarch i386 gcc -o hello helloworld.c"
also creates an x86_64 elf file instead of an i386 one, to get an i386
one I must do: "gcc -m32 -o hello helloworld.c".

This is unfortunate, because even though rpmbuild adds -m32 to the
*FLAGS environment variables things still don't for many packages,
because they for example often ignore LDFLAGS, thus not specifying -m32
when linking, causing things to fail.

I personally would expect setarch i386 gcc -o hello helloworld.c" to
create an i386 elf binary, I haven't filed a bug for this though,
because I believe the current behavior is intended, unfortunate but
intended.

A work around is to create shell script wrappers for gcc, g++ and ld
which always add -m32, put these somewhere outside the standard $PATH
and add the location to PATH when you want to build i386 binaries.


2) rpmbuild ignores setarch
===========================

"setarch i386 rpmbuild -bb foo.spec" Still tries to build an x86_64 foo,
I know "rpmbuild --target i386" works better but still has issues, for
example libdir is still set to /usr/lib64, this is already in bugzilla.

I however still believe that rpmbuild should change its default build
target when using setarch and should call setarch itself when called
with --target, shall I BZ this?


3) pkgconfig ignores setarch
============================
I thought that pkgconfig was supposed to get this right and hence it was
used to implement verious replacement foo-config scripts, but pkgconfig
doesn't get this right. When testing I had only libpng-devel.i386
installed not the x86_64 version:
---
[hans at shalem ~]$ pkg-config --cflags libpng
Package libpng was not found in the pkg-config search path.
Perhaps you should add the directory containing `libpng.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libpng' found
---
Behaves as expected, since it searches /usr/lib64/pkgconfig where there
is no libpng.pc
---
[hans at shalem ~]$ setarch i386 pkg-config --cflags libpng
Package libpng was not found in the pkg-config search path.
Perhaps you should add the directory containing `libpng.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libpng' found
[hans at shalem ~]$ ls -l /usr/lib/pkgconfig/libpng.pc
lrwxrwxrwx 1 root root 11 Oct 15 18:50 /usr/lib/pkgconfig/libpng.pc ->
libpng12.pc
---
Does not behave as expected, it should search /usr/lib/pkgconfig and
find libpng.pc

This can be worked around by doing a "export
PKG_CONFIG_PATH=/usr/lib/pkgconfig"

Shall I BZ this?


4) rpmbuild lets x86_64 packages satisfy BR's when building for i386
====================================================================

The subject says most of it, when doing an rpmbuild --target=i386 I
don't want libXt-devel.x86_64 to satisfy a BR: libXt-devel .

I know things aren't that easy because with something like BR:
desktop-file-utils, the x86_64 version will do fine.

Suggestion: make rpmbuild check the arch of BR's who's name ends with
-devel.

This will still have a few exceptions, but will be a big improvement in
general. BZ?


5) xxx-devel.arch should require xxx.arch not just xxx
======================================================

When I install libXt-devel.i386 I expect it to drag in libXt.i386 and
not to be happy with the already installed libXt.x86_64 .

This will also stop some polution with i386 packages of x86_64 system,
because currently we have the following scenario:

libXt-1.0.2-3.fc6.x86_64 is installed

Users does "yum install libXt-devel.x86_64"

Yum finds libXt-devel-1.0.2-3.1.fc6.x86_64,
which needs libXt-1.0.2-3.1.fc6.x86_64 yum does decides to update the
x86_64 version of libXt and as an added bonus also install the i386
version since both match the requirement of libXt-devel-1.0.2-3.1.fc6.x86_64

Once more if people agree with me here I'll put this in bugzilla.


Let me know what you think & Regards,

Hans