For some builds of petsc 3.1, like debian's package, all c code using petsc needs to be compiled with a c++ compiler. This commit makes fluidity build with Debian's petsc 3.1 package, just point PETSC_DIR to /usr/lib/petscdir/3.1/ and leave PETSC_ARCH empty.
For some builds of petsc 3.1, like debian's package, all c code using petsc needs to be compiled with a c++ compiler. This commit makes fluidity build with Debian's petsc 3.1 package, just point PETSC_DIR to /usr/lib/petscdir/3.1/ and leave PETSC_ARCH empty.

FluidityProject/multifluids,FluidityProject/multifluids,FluidityProject/multifluids,FluidityProject/multifluids