Set CMAKE_CXX_VISIBILITY_PRESET to hidden

This avoids the visibility setting warnings in the linker
(https://github.com/mudge/re2/actions/runs/5631492710/job/15258506852)
and reduces the size of the binaries.

ext/re2/extconf.rb

@@ -340,15 +340,15 @@ def build_with_vendored_libraries
       url: "https://github.com/abseil/abseil-cpp/archive/refs/tags/#{recipe.version}.tar.gz",
       sha256: dependencies['abseil']['sha256']
     }]
-    recipe.configure_options += ['-DABSL_PROPAGATE_CXX_STD=ON']
+    recipe.configure_options += ['-DABSL_PROPAGATE_CXX_STD=ON', '-DCMAKE_CXX_VISIBILITY_PRESET=hidden']
   end
 
   re2_recipe = process_recipe('libre2', dependencies['libre2']['version']) do |recipe|
     recipe.files = [{
       url: "https://github.com/google/re2/releases/download/#{recipe.version}/re2-#{recipe.version}.tar.gz",
       sha256: dependencies['libre2']['sha256']
     }]
-    recipe.configure_options += ["-DCMAKE_PREFIX_PATH=#{abseil_recipe.path}", '-DCMAKE_CXX_FLAGS=-DNDEBUG']
+    recipe.configure_options += ["-DCMAKE_PREFIX_PATH=#{abseil_recipe.path}", '-DCMAKE_CXX_FLAGS=-DNDEBUG', '-DCMAKE_CXX_VISIBILITY_PRESET=hidden']
   end
 
   dir_config("re2", File.join(re2_recipe.path, 'include'), File.join(re2_recipe.path, 'lib'))