remove DOCS from default target and druntime.zip

- These are the raw b&w ddoc html files that nobody uses.

- The distributed druntime docs are generated
  by dlang.org (through the doc target).
move -version=CoreDdoc to DDOCFLAGS

- DOCFMT is typically overriden when calling
  the makefile.
no need to GC scan the .rodata segment

- Also _deh_end will have to live in .data for PIC code
  (Bugzilla 11171), so it can't be used as end of .rodata.
Merge pull request #715 from MartinNowak/dontScanRODATAonFBSD

[dll] FreeBSD must not GC scan .rodata
Replace AssociativeArray struct with UFCS methods
Merge pull request #668 from yebblies/fixaarray

Replace AssociativeArray struct with UFCS methods
Fix for issue 11981
Switch to using pthread_key_t for Thread reference on Posix
Use atomic ops in host test
pthread_key_delete(); Don't use pthread_key_t on OSX
missing else
Merge pull request #719 from radcapricorn/host_test_atomic_ops

DRuntime: Use atomic ops in host test
Merge pull request #718 from radcapricorn/issue_11981

Fix for issue 11981 - deadlock during thread initialization on Posix
Allow calling .get on a const AA
12129: fixed va_start documentation (misspelled parameter name)
Merge pull request #720 from yebblies/aatests

Allow calling .get on a const AA
Merge pull request #721 from rbanderton/fix-issue-12129

12129: fixed va_start documentation (misspelled parameter name)
Fix Issue 12136 - [AA] Associative array `keys` and `values` become non-properties.

Issue URL: https://d.puremagic.com/issues/show_bug.cgi?id=12136
Merge pull request #722 from denis-sh/fix-issue-12136

Fix Issue 12136 - [AA] Associative array `keys` and `values` become non-properties.
fix Issue 12121 - atomicLoad!(MemoryOrder.acq) doesn't require load barrier

[Issue 12121 – atomicLoad!(MemoryOrder.acq) should not emit additional code on X86](https://d.puremagic.com/issues/show_bug.cgi?id=12121)