[systemd-devel] [PATCH 2/5] udev.pc: install to pkgconfiglibdir

[Marc-Antoine Perennou]

On 8 April 2015 at 18:47, Kay Sievers <kay at vrfy.org> wrote:
> On Tue, Apr 7, 2015 at 8:54 PM, Marc-Antoine Perennou
> <Marc-Antoine at perennou.com> wrote:
>> ---
>>  Makefile.am | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/Makefile.am b/Makefile.am
>> index 9fa4223..9b769ee 100644
>> --- a/Makefile.am
>> +++ b/Makefile.am
>> @@ -3725,8 +3725,7 @@ udevconfdir = $(sysconfdir)/udev
>>  dist_udevconf_DATA = \
>>         src/udev/udev.conf
>>
>> -sharepkgconfigdir = $(datadir)/pkgconfig
>> -sharepkgconfig_DATA = \
>> +pkgconfiglib_DATA += \
>>         src/udev/udev.pc
>
> This is all backwards. The systemd.pc file is also in the wrong location.
>
> These GENERIC files are supposed to be found by the primary AND the
> secondary arch at the same time, at the GENERIC location, not in a
> arch-specific libdir.
>
> How would the 32bit build find this file on a 64bit compat-arch/multilib system?
>
> Kay

Well, let's imagine a full cross-compilation toolchain, with
CHOST-prefixed tools.

x86_64 stuff will get built with x86_64-pc-linux-gnu-gcc
i686 stuff will get built with i686-pc-linux-gnu-gcc
(and you could add a lot of non-native archs here like arm, mips & co)

x86_64-pc-linux-gnu-pkg-config will look into /usr/lib64/pkgconfig and
/usr/share/pkgconfig
i686-pc-linux-gnu-pkg-config will look into /usr/lib32/pkgconfig and
/usr/share/pkgconfig

You says that systemd is in the wrong location, so let's see what's
going on with its
current location, and then if we move it to /usr/share

Current location, libdir/pkgconfig/systemd.pc

x86_64-pc-linux-gnu-pkg-config finds /usr/lib64/pkgconfig/systemd.pc containing,
amongst other things, libdir which is arch specific, /usr/lib64 and
systemdutildir
which contains arch-specific binaries (yes, /usr/lib64/systemd/systemd *is* an
ELF64 binary using an x86_64 interpreter.

i686-pc-linux-gnu-pkg-config finds /usr/lib32/pkgconfig/systemd.pc (since it has
been cross-compiled too) and is pretty happy with that.

arm-whatever-pkg-config finds /usr/arm-whatever/lib/systemd.pc and is
happy with it.

If you move it to /usr/share/pkgconfig

x86_64-pc-linux-gnu-pkg-config finds /usr/share/pkgconfig/systemd.pc
and is happy with it

i686-pc-linux-gnu-pkg-config finds /usr/share/pkgconfig/systemd.pc and
tries linking to
x86_64 libraries

arm-whatever-pkg-config finds /usr/share/pkgconfig/systemd.pc and
tries linking to
x86_64 libraries + it gets the path towards binaries its target won't
even be able to execute.


Hope that helps understanding the rational of putting pkgconfig files
pointing to
arch-specific libs/bins into an arch-specific place.


A good example of a pkgconfig file that is ok to install into
/usr/share/pkgconfig is
xorg-macros.pc which only leads to arch-independants macros.