Merge pull request #234 from dawgfoto/fix7995

fix issue 7995
Merge pull request #238 from klickverbot/windows-only-dead-code

Remove Posix/OS X code in Windows-only thread functions.
Expose a thread_setThis() function in core.thread.
Mark some core.stdc.stdio functions pure.
Fix unit tests broken by https://github.com/D-Programming-Language/dmd/pull/994

* Fix private-use code points to Unicode characters
Merge pull request #241 from dheld/master

Fix Unicode unit test breakage
Fix core.sys.windows.windows.LPCVOID

* also reformatted a bit
Merge pull request #242 from denis-sh/fix-LPCVOID

Fix core.sys.windows.windows.LPCVOID
Merge pull request #240 from alexrp/core-stdc-stdio-pure

Mark some core.stdc.stdio functions pure.
fix version specific IMAGEHLP_MODULE64 fields

- we don't use the additional fields and newer versions
  of dbghelp.dll are backwards compatible
remove unused moduleInfo
embedded CV info not loaded with explicit base address

- specifying the base address is only obligatory when
  loading external pdb files which we never do

- the CV function addresses should already have been relocated
use debug(PRINTF) for tracing
don't silently skip symbols without location info
check return value of SymInitialize
use the default module load mechanism

- passing fInvadeProcess=TRUE to SymInitialize loads symbols
  for all modules

- workaround CodeView bug
use the default symbol load paths

- uses same directories but SYSTEMROOT (C:\Windows)
  which didn't made any sense
unused process id
remove dead code
use stack buffer for symbol names

- fix SizeOfStruct = IMAGEHLP_SYMBOL64.sizeof
  according to StackWalk64 documentation