meson: link libm into wallpaper-collections/gallery/rotator tests (fixes aarch64 build)

[mateoalfaro]

Generative AI assistance

AI assistance: disclosed

The commit on this branch carries the required Assisted-by/AI-Scope trailers per AGENTS.md; the patch and report text were validated by the submitter.

Root cause

At commit aef0f372529fb69cbf38f64a427aabdfc0b4a555 (pinned by singularity-desktop master
0ba791f512908c69a03396ae0e05965439187d91), building singularity-desktop on aarch64-linux
fails at the end of the build (all ~2000 targets compile fine) linking exactly three test
executables that share src/core/dynamic_wallpaper.vala:

FAILED: subprojects/singularity-shell/wallpaper-collections-test
FAILED: subprojects/singularity-shell/wallpaper-gallery-test
FAILED: subprojects/singularity-shell/wallpaper-rotator-test

subprojects/singularity-shell/wallpaper-collections-test.p/meson-generated_src_core_dynamic_wallpaper.c.o:
in function `singularity_dynamic_wallpaper_sun_day_terms.constprop.0':
dynamic_wallpaper.c:(.text+0x139c): undefined reference to `sincos'
dynamic_wallpaper.c:(.text+0x4088): undefined reference to `sincos'
dynamic_wallpaper.c:(.text+0x40a0): undefined reference to `cos'
dynamic_wallpaper.c:(.text+0x40cc): undefined reference to `acos'
dynamic_wallpaper.c:(.text+0x42bc): undefined reference to `fmod'
dynamic_wallpaper.c:(.text+0x44bc): undefined reference to `sincos'
dynamic_wallpaper.c:(.text+0x44dc): undefined reference to `sin'
dynamic_wallpaper.c:(.text+0x4510): undefined reference to `acos'
collect2: error: ld returned 1 exit status

Mechanism:

• GCC folds paired sin(x)/cos(x) calls into sincos() at -O2. sincos, sin, cos, acos,
  fmod live in libm, which POSIX requires linking explicitly — they are not in libc.
• These three targets are the only math-using targets in meson.build that don't declare
  cc.find_library('m'). The file already uses this exact pattern elsewhere, e.g.
  the main shell target (line ~660) and recorder_plan_test (line ~748).
• On x86_64 the link succeeds by accident: some dependency carries libm in its DT_NEEDED
  chain and the linker resolves the undefined symbols transitively. On aarch64 (observed on
  NixOS aarch64-linux, glibc, GCC 15) no library in the link closure provides libm, so the
  three links fail.

Fix: add cc.find_library('m') to the three targets' dependency lists, consistent with the
rest of the file.

Reference file view: https://github.com/singularityos-lab/singularity-shell/blob/aef0f372529fb69cbf38f64a427aabdfc0b4a555/meson.build (lines 905–928)

---

The patch

diff --git a/meson.build b/meson.build
index 65b37ac..5789d22 100644
--- a/meson.build
+++ b/meson.build
@@ -904,7 +904,7 @@ install_data('data/icons/singularity-account-secure-mail.svg',
 
 wallpaper_collections_test = executable('wallpaper-collections-test',
   sources: ['src/core/wallpaper_collections.vala', 'src/core/dynamic_wallpaper.vala', 'tests/wallpaper_collections_test.vala'],
-  dependencies: [dependency('gobject-2.0'), dependency('glib-2.0'), dependency('gio-2.0'), gee_dep, json_dep],
+  dependencies: [dependency('gobject-2.0'), dependency('glib-2.0'), dependency('gio-2.0'), gee_dep, json_dep, cc.find_library('m')],
 )
 test('wallpaper-collections', wallpaper_collections_test)
 
@@ -916,14 +916,14 @@ test('wallpaper-rotation-state', wallpaper_rotation_state_test)
 
 wallpaper_gallery_test = executable('wallpaper-gallery-test',
   sources: ['src/core/wallpaper_gallery.vala', 'src/core/dynamic_wallpaper.vala', 'tests/wallpaper_gallery_test.vala'],
-  dependencies: [dependency('gobject-2.0'), dependency('gio-2.0'), gee_dep, json_dep],
+  dependencies: [dependency('gobject-2.0'), dependency('gio-2.0'), gee_dep, json_dep, cc.find_library('m')],
 )
 test('wallpaper-gallery', wallpaper_gallery_test)
 wallpaper_rotator_test = executable('wallpaper-rotator-test',
   sources: ['src/core/wallpaper_collections.vala', 'src/core/wallpaper_gallery.vala', 'src/core/dynamic_wallpaper.vala',
             'src/core/wallpaper_rotation_state.vala', 'src/core/wallpaper_rotator.vala',
             'tests/wallpaper_rotator_test.vala'],
-  dependencies: [dependency('gobject-2.0'), dependency('glib-2.0'), dependency('gio-2.0'), gee_dep, json_dep],
+  dependencies: [dependency('gobject-2.0'), dependency('glib-2.0'), dependency('gio-2.0'), gee_dep, json_dep, cc.find_library('m')],
 )
 test('wallpaper-rotator', wallpaper_rotator_test)