Normalize backend's elf structures with system headers.
Forward to system headers when available.
implement UDA for module declaration
[Refactoring] checkNonAssignmentArrayOp
fix issue 13497 remained case

`AssignExp::semantic` should handle cases in both valid and invalid array operations.
fix Issue 12381 - [ICE] An internal error in e2ir.c while casting array ops
fix Issue 13503 - Bad code with -inline, varargs and auto return
more ErrorStatement recovery
fix Issue 13465 - Segfault by eager semantic2 running in template instantiation
warn on .sort and .reverse usage
deprecate NCEG operator usage
Merge pull request #4027 from WalterBright/nceg-deprecate

deprecate NCEG operator usage
Merge pull request #4024 from 9rnsr/fix13465

Issue 13465 - Segfault by eager semantic2 running in template instantiation
Merge pull request #4014 from 9rnsr/fix13503

[REG2.065] Issue 13503 - Bad code with -inline, varargs and auto return
Merge pull request #4017 from WalterBright/error-statement

more ErrorStatement recovery
make typedef an error
fix Issue 13550 - Inner functions take outer function attributes erroneously
add new cdpopcnt to stub platform
Merge pull request #4031 from 9rnsr/fix13550

[REG2.067a] Issue 13550 - Inner functions take outer function attributes erroneously
Merge pull request #4032 from braddr/fix-stub

add new cdpopcnt to stub platform
Merge pull request #4028 from WalterBright/warn-sort-reverse

warn on .sort and .reverse usage