wizard: fix warnings

.../Source/cmakewizard.cxx: In member function ‘virtual void cmakewizard::AskUser(const char*, cmCacheManager::CacheIterator&)’:
.../Source/cmakewizard.cxx:31:35: warning: conversion to ‘int’ from ‘long unsigned int’ may alter its value [-Wconversion]
   if(!fgets(buffer, sizeof(buffer)-1, stdin))
                                   ^
.../Source/cmakewizard.cxx: In member function ‘virtual bool cmakewizard::AskAdvanced()’:
.../Source/cmakewizard.cxx:70:35: warning: conversion to ‘int’ from ‘long unsigned int’ may alter its value [-Wconversion]
   if(!fgets(buffer, sizeof(buffer)-1, stdin))

The compiler is (partly) right here: sizeof() returns a size_t, which often is
bigger as as int as it is unsigned long or something similar. Add an explicit
cast to get rid of that warning here, the buffer has a size of 4KiB, so the
value will fit into an int on all sane platforms.
simplify control flow

Checking if a byte is 0 before checking it for something else doesn't do
anything useful. Also one can be sure that it can't be anything wanted if the
value was set to 0 immediately before.
Merge topic 'wizard-cleanup' into next

d5fa327 simplify control flow
f1d27bf wizard: fix warnings
drop the unused local typedef LinkLine
Merge topic 'LinkLine-typedef' into next

1c1246e drop the unused local typedef LinkLine