diff --git a/ext/re2/extconf.rb b/ext/re2/extconf.rb
index 278f76b..853ef00 100644
--- a/ext/re2/extconf.rb
+++ b/ext/re2/extconf.rb
@@ -363,6 +363,8 @@ def build_with_vendored_libraries
   raise 'Unable to run pkg-config --libs --static' unless $?.success?
 
   lib_paths = [File.join(abseil_recipe.path, 'lib'), File.join(re2_recipe.path, 'lib')]
+  version = xpopen(['pkg-config', '--version'], err: %i[child out], &:read)
+  STDERR.puts "=== pkg-config version: #{version}"
   STDERR.puts "=== flags: #{flags}"
   add_static_ldflags(flags, lib_paths)
   build_extension(true)