sync backend files with dmc
fix Issue 11395 - link error (struct+opEquals) on separate compilation
Merge pull request #2697 from WalterBright/sync-with-dmc

sync backend files with dmc
Merge pull request #2698 from 9rnsr/fix11395

[REG2.064a] Issue 11395 - link error (struct+opEquals) on separate compilation
fix ElfObj::common_block size

- fix Issue 11237

- Need to explicitly pass the size of the defined common
  symbol as it can't be computed from the symbol type.
struct initializer are not weak symbols

- fix Issue 11237

- The function outdata will take care of the
  BSS optimization for DTallzeros.
add test case for Issue 11237

- fix OS name of linux in Makefile
Merge pull request #2701 from dawgfoto/fix11237

fix Issue 11237
fix Issue 11423 - Error: new can only create structs, dynamic arrays or class objects, not _error_'s
Merge pull request #2710 from 9rnsr/fix11423

Issue 11423 - Error: new can only create structs, dynamic arrays or class objects, not _error_'s