Bug#1088 - add -mpreferred-stack-boundary=4 to gcc flags to always work with...

Bug#1088 - add -mpreferred-stack-boundary=4 to gcc flags to always work with -msse2 flag.  Some GCC versions dropped forcing boundary=4

git-svn-id: https://redoubt.ligo-wa.caltech.edu/svn/advLigoRTS/trunk@4350 6dcd42c9-f523-4c6d-aada-af552506706e