rebased and set back WINDOWS_CCONV

Author: Mistuke

System/Process/Windows.hsc

@@ -44,10 +44,17 @@ import System.Win32.Process (getProcessId)
 
 -- The double hash is used so that hsc does not process this include file
 ##include "processFlags.h"
-#include "windows_cconv.h"
 
 #include <fcntl.h>     /* for _O_BINARY */
 
+##if defined(i386_HOST_ARCH)
+## define WINDOWS_CCONV stdcall
+##elif defined(x86_64_HOST_ARCH)
+## define WINDOWS_CCONV ccall
+##else
+## error Unknown mingw32 arch
+##endif
+
 throwErrnoIfBadPHandle :: String -> IO PHANDLE -> IO PHANDLE
 throwErrnoIfBadPHandle = throwErrnoIfNull