尽快推进：收紧dlfcn shim源码锚点

check-linuxcnc-wasm-shims-source-map.sh

@@ -178,7 +178,31 @@ for shim_path, linuxcnc_sources in expected_shims.items():
 
 runtime_shim = Path("core/wasm_shims/linuxcnc_runtime_shim.cc").read_text(encoding="utf-8")
 runtime_probe = Path("core/wasm_shims/cnc_sim_wasm_runtime_probe_main.cc").read_text(encoding="utf-8")
+dlfcn_shim = Path("core/wasm_shims/dlfcn.cc").read_text(encoding="utf-8")
+dlfcn_header = Path("core/wasm_shims/dlfcn.h").read_text(encoding="utf-8")
 gettext_shim = Path("core/wasm_shims/gettext_shim.cc").read_text(encoding="utf-8")
+for needle in [
+    "#define RTLD_GLOBAL 0x00100",
+    "#define RTLD_NOW 0x00002",
+    "void *dlopen(const char *filename, int flags);",
+    "void *dlsym(void *handle, const char *symbol);",
+    "char *dlerror(void);",
+    "int dlclose(void *handle);",
+]:
+    if needle not in dlfcn_header:
+        raise SystemExit(f"dlfcn shim header missing LinuxCNC loader boundary: {needle}")
+for needle in [
+    "dynamic loading is unavailable in wasm-safe probe",
+    "void *dlopen(const char *, int)",
+    "return nullptr;",
+    "void *dlsym(void *, const char *)",
+    "char *dlerror(void)",
+    "return last_error;",
+    "int dlclose(void *)",
+    "return 0;",
+]:
+    if needle not in dlfcn_shim:
+        raise SystemExit(f"dlfcn shim missing unavailable-loader boundary: {needle}")
 for needle in [
     "extern \"C\" char *gettext(const char *msgid)",
     "return const_cast<char *>(msgid ? msgid : \"\");",
@@ -280,6 +304,8 @@ for phrase in [
     "CMake `linuxcnc_wasm_safe_probe_shims` set",
     "RS274/WASM manifest",
     "browser-safe LinuxCNC adaptations",
+    "LinuxCNC `interp_base.cc` dynamic loader calls",
+    "unavailable-loader returns",
     "LinuxCNC `_()` diagnostic call sites",
     "browser gettext catalogs unavailable",
     "LinuxCNC NML status constructors",