Merge pull request #35 from SpringMT/fix-declspec

Fix declspec

Author: SpringMT

.github/workflows/ruby.yml

@@ -15,15 +15,15 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.5', '2.6', '2.7', '3.0']
+        ruby-version: ['2.6', '2.7', '3.0', '3.1']
 
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby
     # To automatically get bug fixes and new Ruby versions for ruby/setup-ruby,
     # change this to (see https://github.com/ruby/setup-ruby#versioning):
     # uses: ruby/setup-ruby@v1
-      uses: ruby/setup-ruby@473e4d8fe5dd94ee328fdfca9f8c9c7afc9dae5e
+      uses: ruby/setup-ruby@168d6a54b412713c0ed60998a78093a270ca8d84
       with:
         ruby-version: ${{ matrix.ruby-version }}
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically

ext/zstdruby/extconf.rb

@@ -1,6 +1,7 @@
 require "mkmf"
 
 $CFLAGS = '-I. -O3 -std=c99'
+$CPPFLAGS += " -fdeclspec" if CONFIG['CXX'] =~ /clang/
 
 Dir.chdir File.expand_path('..', __FILE__) do
     $srcs = Dir['**/*.c']