diff --git a/spec/ruby/optional/capi/spec_helper.rb b/spec/ruby/optional/capi/spec_helper.rb
index f43a9f345b..373012a869 100644
--- a/spec/ruby/optional/capi/spec_helper.rb
+++ b/spec/ruby/optional/capi/spec_helper.rb
@@ -26,15 +26,15 @@ def compile_extension(name)
   libruby_so = RbConfig::CONFIG['LIBRUBY_SO']
   ruby_library = "#{RbConfig::CONFIG['libdir']}/#{libruby_so}"
   unless libruby_so and File.exist?(ruby_library)
-    # Statically-compiled lib in the binary
-    ruby_library = ENV['RUBY_EXE']
+    # Statically-compiled lib in the binary, ignore this check
+    ruby_library = nil
   end
 
   return lib if File.exist?(lib) and
                 File.mtime(lib) > File.mtime("#{extension_path}/rubyspec.h") and
                 File.mtime(lib) > File.mtime("#{extension_path}/#{ext}.c") and
                 File.mtime(lib) > File.mtime(ruby_header) and
-                File.mtime(lib) > File.mtime(ruby_library) and
+                (!ruby_library || File.mtime(lib) > File.mtime(ruby_library)) and
                 true            # sentinel
 
   # Copy needed source files to tmpdir