scheds-rust: build rust schedulers in sequence

scheds/rust/meson.build

@@ -1,5 +1,23 @@
+# the previous scheduler in the compile sequence
+sched = []
+
+# to add a new scheduler, assign the output of your custom_target to sched
+# and add sched as a dependency to your custom_target. For example:
+#
+# sched = custom_target('scx_mysched',
+#                       ...
+#                       depends: [mydep, sched],
+#                       build_always_stale: true)
 subdir('scx_layered')
 subdir('scx_rusty')
 subdir('scx_rustland')
 subdir('scx_rlfifo')
 subdir('scx_lavd')
+
+# the target to compile all rust schedulers
+custom_target('rust_scheds',
+              input: 'meson.build',
+              output: '@PLAINNAME@.__PHONY__',
+              command: ['touch', '@PLAINNAME@.__PHONY__'],
+              depends: sched,
+              build_by_default: true)

scheds/rust/scx_lavd/meson.build

@@ -1,7 +1,8 @@
-custom_target('scx_lavd',
+sched = custom_target('scx_lavd',
               output: '@PLAINNAME@.__PHONY__',
               input: 'Cargo.toml',
               command: [cargo, 'build', '--manifest-path=@INPUT@', '--target-dir=@OUTDIR@',
                         cargo_build_args],
               env: cargo_env,
-              build_by_default: true)
+              depends: [sched],
+              build_always_stale: true)

scheds/rust/scx_layered/meson.build

@@ -1,8 +1,8 @@
-custom_target('scx_layered',
+sched = custom_target('scx_layered',
               output: '@PLAINNAME@.__PHONY__',
               input: 'Cargo.toml',
               command: [cargo, 'build', '--manifest-path=@INPUT@', '--target-dir=@OUTDIR@',
                         cargo_build_args],
               env: cargo_env,
-              depends: [libbpf, bpftool_target],
-              build_by_default: true)
+              depends: [libbpf, bpftool_target, sched],
+              build_always_stale: true)

scheds/rust/scx_rlfifo/meson.build

@@ -1,8 +1,8 @@
-custom_target('scx_rlfifo',
+sched = custom_target('scx_rlfifo',
               output: '@PLAINNAME@.__PHONY__',
               input: 'Cargo.toml',
               command: [cargo, 'build', '--manifest-path=@INPUT@', '--target-dir=@OUTDIR@',
                         cargo_build_args],
               env: cargo_env,
-              depends: [libbpf, bpftool_target],
-              build_by_default: true)
+              depends: [libbpf, bpftool_target, sched],
+              build_always_stale: true)

scheds/rust/scx_rustland/meson.build

@@ -1,8 +1,8 @@
-custom_target('scx_rustland',
+sched = custom_target('scx_rustland',
               output: '@PLAINNAME@.__PHONY__',
               input: 'Cargo.toml',
               command: [cargo, 'build', '--manifest-path=@INPUT@', '--target-dir=@OUTDIR@',
                         cargo_build_args],
               env: cargo_env,
-              depends: [libbpf, bpftool_target],
-              build_by_default: true)
+              depends: [libbpf, bpftool_target, sched],
+              build_always_stale: true)

scheds/rust/scx_rusty/meson.build

@@ -1,8 +1,8 @@
-custom_target('scx_rusty',
+sched = custom_target('scx_rusty',
               output: '@PLAINNAME@.__PHONY__',
               input: 'Cargo.toml',
               command: [cargo, 'build', '--manifest-path=@INPUT@', '--target-dir=@OUTDIR@',
                         cargo_build_args],
               env: cargo_env,
-              depends: [libbpf, bpftool_target],
-              build_by_default: true)
+              depends: [libbpf, bpftool_target, sched],
+              build_always_stale: true)