linux: Fix TLS error on dlopen of libcef.so (fixes #3616)

patch/patch.cfg

@@ -826,5 +826,10 @@ patches = [
     # hidden menu items.
     # https://github.com/chromiumembedded/cef/issues/3577
     'name': 'ui_menu_model_3577'
+  },
+  {
+    # linux: Fix cannot allocate memory in static TLS block in dlopen libcef.so
+    # https://github.com/chromiumembedded/cef/issues/3616
+    'name': 'third_party_sentencepiece_3616'
   }
 ]

patch/patches/third_party_sentencepiece_3616.patch

@@ -0,0 +1,33 @@
+diff --git third_party/sentencepiece/src/src/util.cc third_party/sentencepiece/src/src/util.cc
+index 538b00b..61c4e5d 100644
+--- third_party/sentencepiece/src/src/util.cc
++++ third_party/sentencepiece/src/src/util.cc
+@@ -16,6 +16,7 @@
+ 
+ #include <atomic>
+ #include <iostream>
++#include <memory>
+ 
+ namespace sentencepiece {
+ 
+@@ -187,8 +190,18 @@ std::mt19937 *GetRandomGenerator() {
+ }
+ #else
+ std::mt19937 *GetRandomGenerator() {
+-  thread_local static std::mt19937 mt(GetRandomGeneratorSeed());
+-  return &mt;
++  // Thread-locals occupy stack space in every thread ever created by the
++  // program, even if that thread never uses the thread-local variable.
++  //
++  // https://maskray.me/blog/2021-02-14-all-about-thread-local-storage
++  //
++  // sizeof(std::mt19937) is several kilobytes, so it is safer to put that on
++  // the heap, leaving only a pointer to it in thread-local storage.  This must
++  // be a unique_ptr, not a raw pointer, so that the generator is not leaked on
++  // thread exit.
++  thread_local static auto mt =
++      std::make_unique<std::mt19937>(GetRandomGeneratorSeed());
++  return mt.get();
+ }
+ #endif
+ }  // namespace random