#1 Fix and tag a few compiler warnings.

[Roger Wolff]

Sometimes the compiler emits; warning: ‘segtype’ may be used uninitialized in this function

Sometimes the compiler is wrong. Say the assignment and use of the variable are both
enclosed by the same condition.
Sometimes the initialization depends on user input. I've tried to mark those with XXX .(which means: Needs fixing).
Sometimes it depends on the correct setting of an integer variable to just a few possible values. Same resolution.

And then I got tired, so I haven't fixed all those compiler warnings.

I really recommend someone with more familiarity with the code to review my patches.

[Roger Wolff]

warningfixes.