Add POPCNT intrinsics to core.bitop
Merge pull request #952 from WalterBright/addPOPCNT

Add POPCNT intrinsics to core.bitop
Revert "Issue 7942 - Appending different string types corrupts memory"

This reverts commit d0f8bca7ad1eea1b8e9e2774fc84a1af7ce73815.
Merge pull request #953 from yebblies/revert7942

Revert "Issue 7942 - Appending different string types corrupts memory"