diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index b5a8b694c94..fb5127bac54 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -383,6 +383,8 @@ fn configure_cmake(
             cfg.define("CMAKE_SYSTEM_NAME", "Windows");
         } else if target.contains("haiku") {
             cfg.define("CMAKE_SYSTEM_NAME", "Haiku");
+        } else if target.contains("solaris") || target.contains("illumos") {
+            cfg.define("CMAKE_SYSTEM_NAME", "SunOS");
         }
         // When cross-compiling we should also set CMAKE_SYSTEM_VERSION, but in
         // that case like CMake we cannot easily determine system version either.