Fix build for gcc < 4.6
Fix build for gcc < 4.6

With a cast through. Previously the fix for cast qualification warning relied on
GCC warning suppression that was added after GCC 4.6

wcs1only/s2n,colmmacc/s2n,wcs1only/s2n,colmmacc/s2n,alexeblee/s2n,awslabs/s2n,awslabs/s2n,awslabs/s2n,alexeblee/s2n,wcs1only/s2n,awslabs/s2n,colmmacc/s2n,PKRoma/s2n,colmmacc/s2n,alexeblee/s2n,wcs1only/s2n,wcs1only/s2n,awslabs/s2n,alexeblee/s2n,PKRoma/s2n,alexeblee/s2n,PKRoma/s2n,PKRoma/s2n,awslabs/s2n,PKRoma/s2n,PKRoma/s2n,wcs1only/s2n,alexeblee/s2n,PKRoma/s2n,wcs1only/s2n,colmmacc/s2n,wcs1only/s2n,colmmacc/s2n,PKRoma/s2n