This fixes flt_arith2flt() when sizeof(arith) != 4, where arith is
long. When cemcom.ansi sees an expression like d + 1 (where d is some
double), it calls flt_arith2flt() to convert 1 to floating-point. On
machines where sizeof(arith) != 4, the code did n >>= 1 when n should
not have been changed. If n was 1, then n == 0 became true. This
caused the code to convert 1 or -1 to 0.0.
My fix assumes sizeof(arith) >= 8, so I can use n >> 32. Machines
with sizeof(arith) of 5 to 7 would need to do (uarith)n >> 32, where
uarith must be an unsigned integer type of same size as arith.
In startrek.c, the Enterprise can now dock with a starbase. The
compiler no longer translates s1 - 1 to s1 - 0.0 and s1 + 1 to s1 +
0.0, so the game now looks for starbases next to the Enterprise.
