[Build] (P13 W7): the library links from module OBJECT targets along the ratchet's partition, and a server-only link check target must link without the frontend modules.

tools/server_link_check/Exempt.cpp

@@ -0,0 +1,19 @@
+// MobileGL - tools/server_link_check/Exempt.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// P13 W7 (D12): the one definition every named exemption of the server-only link check resolves to
+// (scripts/ci/server_link_check.py writes `--defsym=<symbol>=mgl_server_link_check_exempt` for each
+// frontend reference the link ratchet's baseline names). The check target is a link proof and is
+// never loaded; reaching this would mean a server image called into the frontend half.
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" [[noreturn]] void mgl_server_link_check_exempt() {
+    std::fputs("MobileGL server link check: an exempted frontend symbol was called\n", stderr);
+    std::abort();
+}