libdir detection is buggy in many cases

[Jehan]

I have been cross-compiling json-glib (which uses meson) for 32-bit and it would install it inside lib64/:

The compilation is fine and renders proper 32-bit:

$ file lib64/libjson-glib-1.0.so.0.301.0
lib64/libjson-glib-1.0.so.0.301.0: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, not stripped

Only the path is wrong.
Also since I am building from a 64-bit platform, this may be the problem, of course. Basically do not decide on the installation path from the build OS, but from the host one.
I filled a bug in json-glib, but they tell me the problem is with meson: https://bugzilla.gnome.org/show_bug.cgi?id=784532

Also for information, I do not consider the proposed solution of setting --libdir valid. I know of this option, which exists on all other build systems (and that's a good option), but it should not be a reason not to have sane defaults.

[jpakkane]

The default for that should probably be settable in the cross file...

[Jehan]

What settings would it be? sizeof_int?
In any case, when cross-compiling, if such a settings is not set, that should default to lib/ (this can never go wrong).

Is there no good way to determine if the target is 64 bit? I could think of checking gcc -dumpmachine output, and if it has a 64 in it, assuming 64-bit. Now that's dirty and I can say for sure it is not totally reliable (for instance i686-w64-mingw32-gcc target is 32-bit).

As a last comment, I would not be against just defaulting to lib/ always, even when the target is know 64-bit. The directory lib64/ is somewhat considered deprecated by many distributions and I think all 64-bit distributions will look in lib/ as well as lib64/ anyway.

[jpakkane]

What settings would it be? sizeof_int?

I was thinking more in the line of libdir...

[Jehan]

I was thinking more in the line of libdir...

In which section do you set this? I tried under every section in your doc (host_machine, binaries, properties… tried them all just to be sure) but it didn't set libdir.

Edit: or I realize suddenly, did you actually mean that you should add this? Hence the feature is not there yet?

[jpakkane]

did you actually mean that you should add this

Yes.

[topilski]

ping

[TheQwertiest]

The following changes were made in meson 0.50.0 that address the issue discussed here:

• Added support for setting libdir via crossfile (via Extend native files to store install path information #4743).
• Default libdir for cross compilation was changed to lib (via Default libdir is "lib" when cross compiling. Closes #2535. #4680).

[dcbaker]

I think this should have been closed by 4743 as well. I'm going to close this.