build: update meson.build for workspace — add PAM module and display binary targets

meson.build

@@ -30,6 +30,36 @@ cargo_target = custom_target(
   build_by_default: true
 )
 
+# PAM module (.so with C ABI — no resources needed, Cargo self-contained)
+pam_cargo = custom_target(
+  'ahfail-pam-cargo-build',
+  input: ['crates/ahfail-pam/src/lib.rs', 'Cargo.toml'],
+  output: ['libahfail_pam.so'],
+  command: [
+    'sh', '-c',
+    'cargo build --release -p ahfail-pam --target-dir "@OUTDIR@/target" && cp "@OUTDIR@/target/release/libahfail_pam.so" "@OUTPUT@"'
+  ],
+  build_by_default: true,
+  install: true,
+  install_dir: get_option('libdir') / 'ahfail',
+  install_mode: 'rwxr-xr-x'
+)
+
+# Display binary (embeds GResources via its own build.rs)
+display_cargo = custom_target(
+  'ahfail-display-cargo-build',
+  input: ['crates/ahfail-display/src/main.rs', 'Cargo.toml'],
+  output: ['ahfail-display'],
+  command: [
+    'sh', '-c',
+    'cargo build --release -p ahfail-display --target-dir "@OUTDIR@/target" && cp "@OUTDIR@/target/release/ahfail-display" "@OUTPUT@"'
+  ],
+  build_by_default: true,
+  install: true,
+  install_dir: get_option('libdir') / 'ahfail',
+  install_mode: 'rwxr-xr-x'
+)
+
 libahfail = shared_library(
   'ahfail-module',
   resources,