Fix build breakage on old versions of SuiteSparse.

SuiteSparse_long is only defined in recent versions of SuiteSparse
as the index variable type for large matrices. In older versions
UF_long was used. Ubuntu still ships with an older version of
SuiteSparse, so an ifdef is needed to fix the build.

This patch has been tested on mac and on linux with older and
newer versions of SuiteSparse.

Change-Id: I4ada86d7973784a79bde4afec13ce3ca4e8dc225
1 file changed