Build C versions of dav1d tools and tests against librav1d

Closes #803.

Can be toggled on off via the test_rust meson configuration option.

meson.build

@@ -472,7 +472,27 @@ endif
 # Generate config.h
 config_h_target = configure_file(output: 'config.h', configuration: cdata)
 
+# Use --out-dir instead of --target-dir to fully control where librav1d.a goes.
+# Using --target-dir would put it in a subdirectory. The --out-dir option is
+# currently unstable so we need to tell cargo to enable those.
+# FIXME: this will only work if the host matches the build target.
+cargo_command = [
+    'cargo', 'build', '--lib',
+    '-Z', 'unstable-options',
+    '--out-dir', meson.current_build_dir()
+]
+if get_option('buildtype') == 'release'
+    cargo_command += ['--release']
+endif
 
+librav1d = custom_target(
+    'librav1d',
+    output: 'librav1d.a',
+    input: ['lib.rs'],
+    command: cargo_command,
+    install: true,
+    install_dir: get_option('libdir')
+)
 
 #
 # Include subdir meson.build files

tests/meson.build

@@ -135,7 +135,7 @@ if get_option('enable_tools')
             dav1d_input_objs.extract_objects('input/input.c', 'input/ivf.c'),
         ],
         include_directories: [dav1d_inc_dirs, include_directories('../tools')],
-        link_with: libdav1d,
+        link_with: get_option('test_rust') ? librav1d : libdav1d,
         dependencies: [
             thread_dependency,
             rt_dependency,
@@ -149,22 +149,9 @@ if get_option('test_rust')
     test_rust_path = get_option('test_rust_path')
     seek_stress_test_rust_path = get_option('seek_stress_test_rust_path')
 
-    # HACK: If we're trying to test the Rust build, override the `dav1d` and
-    # `seek_stress` executables to point to the versions produced by Cargo.
-    # This will test the Rust executables instead of the C versions.
-    if test_rust_path == ''
-        if get_option('debug')
-            profile = 'debug'
-        else
-            profile = 'release'
-        endif
-        test_rust_path = '../target/' + profile + '/dav1d'
-        test_rust_path = join_paths(meson.current_source_dir(), test_rust_path)
-        dav1d = find_program(test_rust_path, required: true)
-        seek_stress_test_rust_path = '../target/' + profile + '/seek_stress'
-        seek_stress_test_rust_path = join_paths(meson.current_source_dir(), seek_stress_test_rust_path)
-        seek_stress = find_program(seek_stress_test_rust_path, required: true)
-    else
+    # We're trying to test the Rust build, override the `dav1d` and
+    # `seek_stress` executables to point to the versions given during setup.
+    if test_rust_path != ''
         # Adjust relative paths so one can use binary paths relative to project
         # top dir rather than relative to the location of the test subdirectory.
         dav1d = files(join_paths('../', get_option('test_rust_path')))

tools/meson.build

@@ -111,7 +111,11 @@ dav1d = executable('dav1d',
     dav1d_rc_obj,
     rev_target, cli_config_h_target,
 
-    link_with : [libdav1d, dav1d_input_objs, dav1d_output_objs],
+    link_with : [
+        get_option('test_rust') ? librav1d : libdav1d,
+        dav1d_input_objs,
+        dav1d_output_objs
+        ],
     include_directories : [dav1d_inc_dirs],
     dependencies : [
         getopt_dependency,