Move place of 'import core.sys.posix.sys.mman'.

The 2nd import of module core.sys.posix.sys.mman is moved in an else block. As result, method freeStack uses the same traits as method allocStack.

Background is that the early import creates a reference to the Posix module on Windows. This gives an linker error on Windows if the Posix module is not compiled.
I/O intrinsics are only available with DMD.
Fix monitor_.d/critical_.d for Windows, remove C implementation.
Update Makefile for Win32/Win64.
Merge pull request #302 from ibuclaw/monitord

Fix monitor_.d/critical_.d for Windows, remove C implementation.
Add more extensive docs to core.memory.
Correct version posix => Posix in unittest.
Merge pull request #305 from ibuclaw/unittest

Correct version posix => Posix in unittest.
remving the .c files removed ref to snn.lib
Win64 exception handling
Win64 variadics
Win64 update for stdio
@trusted nothrow issue 8651 #8651
support Win64 profiling
Fix TypeInfo_Function in object.di
Merge pull request #307 from jpf91/patch-2

Fix TypeInfo_Function size in object.di
fix Win64 eh
varargin64 varargs issues
Making Throwable and derived classes constructors @safe/pure/nothrow.

This is supplemental change for fixing issue 8150.
Constructing throwable object can be @sage, pure, and nothrow.
Merge pull request #309 from 9rnsr/fix8150

Making Throwable and derived classes constructors @safe/pure/nothrow.