Dependency-related regression in 1.5.0rc1

[thierryreding]

Describe the bug
When trying to build libepoxy with the latest meson 1.5.0rc1, I see issues with some of the test programs not linking properly against libX11. libepoxy doesn't seem to be the problem here, since meson 1.4.0 works fine.

I was able to bisect this to commit 6d713e4 ("dependency: define equality and hash operators for Dependency"). Reverting that commit fixes the regression.

To Reproduce
Download the latest libepoxy, extract and build using:

$ mkdir libepoxy-1.5.0/build && cd libepoxy-1.5.0/build
$ meson setup ..
$ ninja

And see it fail to link various GLX, GLES tests.

Expected behavior
libepoxy should build without any errors.

system parameters

• Is this a cross build or just a plain native build (for the same computer)?
  Happens with both native and cross builds.
• what operating system (e.g. MacOS Catalina, Windows 10, CentOS 8.0, Ubuntu 18.04, etc.)
  Arch Linux, but I expect it to be distribution agnostic.
• what Python version are you using e.g. 3.8.0
  Python 3.12.3
• what meson --version
  meson 1.5.0.rc1
• what ninja --version if it's a Ninja build
  ninja 1.12.1

[thierryreding]

@dcbaker any idea what could be causing this? Maybe as an additional data point: in the build log for libepoxy I don't see any of the linker arguments for libX11, though I do see the one for libdl. X11 is found via dependency() and ultimately pkg-config, whereas libdl is found using cc.find_library(), so that's probably why they behave differently.

[eli-schwartz]

See also https://bugs.gentoo.org/935443