Otherwise gcc can default to the "sysv_abi" (as opposed to the "ms_abi") calling convention on X64, causing problems like <http://sourceforge.net/mailarchive/message.php?msg_id=30356166>.

Contributed-under: TianoCore Contribution Agreement 1.0

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: lpleahy


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14148 6f19259b-4bc3-4df7-8a09-765794883524
Contributed-under: TianoCore Contribution Agreement 1.0

Signed-off-by: Frank Fan <frank@asix.com.tw>
Reviewed-by: lpleahy


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14149 6f19259b-4bc3-4df7-8a09-765794883524