fix Issue 13403 - [ICE][2.067Alpha] Internal error: backend\type.c 332 with new package protection extension.
use checkedint to check overflow
Merge pull request #3949 from WalterBright/overflow-check

use checkedint to check overflow
Merge pull request #3940 from 9rnsr/fix13403

Issue 13403 - [ICE][2.067Alpha] Internal error: backend\type.c 332 with new package protection extension.
Add test for worksforme bug 6405.
Merge pull request #3974 from quickfur/test6405

Add test for worksforme bug 6405.
volatile is now an error
Merge pull request #3977 from WalterBright/noVolatile

volatile is now an error
Create builtin for popcnt.

As suggested by @klickverbot popcnt should be a builtin as it is now an intrinsic.