Disable fork spec broken by recent libffi.

rubygem-ffi.spec

@@ -72,6 +72,10 @@ sed -i '/it "add two long double numbers" do/a\
     skip' spec/ffi/long_double_spec.rb
 %endif
 
+# Recent libffi corrupts dynamically allocated closures with call to fork.
+# https://bugzilla.redhat.com/show_bug.cgi?id=2040380
+mv spec/ffi/fork_spec.rb{,.disabled}
+
 RUBYOPT="-I$(dirs +1)%{gem_extdir_mri}" rspec spec
 popd
 
@@ -97,6 +101,9 @@ popd
 %{gem_instdir}/rakelib/ffi_gem_helper.rb
 
 %changelog
+* Thu Jan 27 2022 Vít Ondruch <vondruch@redhat.com> - 1.15.5-2
+- Disable fork spec broken by recent libffi.
+
 * Thu Jan 27 2022 Mamoru TASAKA <mtasaka@fedoraproject.org> - 1.15.5-2
 - F-36: rebuild against ruby31