meson: Add indexmap rust dependencies

Signed-off-by: Christian Gmeiner <cgmeiner@igalia.com>
Reviewed-by: @LingMan
Reviewed-by: Eric Engestrom <eric@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28869>

subprojects/packagefiles/equivalent/meson.build

@@ -0,0 +1,18 @@
+project(
+  'equivalent',
+  'rust',
+  version : '1.0.1',
+  license :'MIT OR Apache-2.0',
+)
+
+lib = static_library(
+  'equivalent',
+  'src/lib.rs',
+  override_options : ['rust_std=2021', 'build.rust_std=2021'],
+  rust_abi : 'rust',
+  native : true,
+)
+
+dep_equivalent = declare_dependency(
+  link_with : [lib],
+)