Merge pull request #884 from rainers/fix_13111

Fix 13111: GC.realloc returns invalid memory for large reallocation
Merge pull request #889 from MartinNowak/fix13025

fix Issue 13025 - Tools repository does not build on Ubuntu
Merge pull request #890 from klickverbot/fix-checkedint-umul

Fix issue 12958 - core.checkedint.mulu is broken.
Merge pull request #891 from AndrewEdwards/2.066

Regression fixes for 2.066.0-b4