Convert any remaining uses of fprintf(stderr, "warning:"...
to use warn_report() instead. This helps standardise on a single
method of printing warnings to the user.

All of the warnings were changed using this command:
  find ./* -type f -exec sed -i 's|fprintf(.*".*warning[,:] |warn_report("|Ig' {} +

The #include lines and chagnes to the test Makefile were manually
updated to allow the code to compile.

Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Message-Id: <2c94ac3bb116cc6b8ebbcd66a254920a69665515.1503077821.git.alistair.francis@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>