Some large file support enhancements

The normal functions should be aliases to the *64 functions,
even if _LARGEFILE64_SOURCE is false. _LARGEFILE64_SOURCE is
more or less deprecated.
Added core.sys.posix.grp (from Posix <grp.h>).

No Solaris declarations for now.
Added core.sys.posix.grp to all make files.
Added XSI prototypes.
Fix a few issues in posix.mak
Remove debug echo
Put the optional prototypes into per-platform version statements.
Merge pull request #374 from andralex/master

Fix a few issues with posix.mak
Added nothrow...
Made the void() functions trusted.
Merge pull request #373 from s-ludwig/master

Add core.sys.posix.grp to complement core.sys.posix.pwd
Add an LREF and document CArgs properly.
Merge pull request #375 from AndrejMitrovic/FixCArgsDocs

Add an LREF and document CArgs properly.
cleanup OS detection

- the wrong variable was set for OpenBSD and Solaris
fix memory leak

- remove implicit ModuleGroup.free() call in ModuleInfo.runDtors()
- free module array passed to ModuleGroup constructor on any
  platform but Win32
Merge pull request #377 from dawgfoto/fixLeak

fix memory leak
Merge pull request #376 from dawgfoto/cleanupMakefile

cleanup OS detection
rename rt.util.string.intToString -> uintToString
Merge pull request #379 from dawgfoto/uintToString

rename rt.util.string.intToString -> uintToString
fix memory leak for core.thread.slock Mutex