Add an ExternalCompilerOptions parameter for use with MSBuild on the command line. This is necessary for continuous integration to pass D3D11 mode build flags. TRAC #22555 Signed-off-by: Geoff Lang Signed-off-by: Shannon Woods Author: Jamie Madill git-svn-id: https://angleproject.googlecode.com/svn/branches/es3proto@2114 736b8ea6-26fd-11df-bfd4-992fa37f6226