Fix clang and MSVC warnings/errors.

src/multiwinner/auction.cc

@@ -18,12 +18,10 @@ int r_auction::elect_and_update(std::vector<bool> & elected,
 	// to the sum (for all non-elected candidates). Note the potential
 	// for vote-management.
 	size_t counter = 0;
-	double voters = 0;
 
 	for (election_t::const_iterator pos = ballots.begin(); pos !=
 		ballots.end(); ++pos) {
 		assert(pos->rated);
-		voters += pos->get_weight(); // not req'd?
 
 		double adjust = 0; // maximum if not cumulative, sum if so.
 		ordering::const_iterator sec;

src/multiwinner/qpq.cc

@@ -76,7 +76,7 @@ std::list<size_t> QPQ::get_council(std::vector<bool> & eliminated,
 		contributing_weights(num_candidates), quotients(num_candidates);
 
 	std::list<size_t> council;
-	size_t num_elected = 0, num_elim = 0;
+	size_t num_elected = 0;
 
 	std::vector<bool> elected(num_candidates, false);
 
@@ -104,18 +104,15 @@ std::list<size_t> QPQ::get_council(std::vector<bool> & eliminated,
 		counter = 0;
 
 		double inactive_ballot_fraction = 0,
-			   active_ballots = 0, sum_weights = 0;
+			   active_ballots = 0;
 
 		// Bah dual track. Get the active and inactive ballot data.
 
 		for (pos = ballots.begin(); pos != ballots.end(); ++pos) {
 			ordering::const_iterator contribute =
 				ballot_contribution(eliminated, elected, *pos);
 
-			sum_weights += elect_fraction[counter] * pos->get_weight();
-
 			if (contribute == pos->contents.end()) {
-				//inactive_ballots += pos->get_weight();
 				inactive_ballot_fraction +=
 					elect_fraction[counter] * pos->get_weight();
 			} else {
@@ -228,7 +225,6 @@ std::list<size_t> QPQ::get_council(std::vector<bool> & eliminated,
 			// reset set to true, tail-recurse. Otherwise, just loop
 			// through.
 			eliminated[lowest] = true;
-			++num_elim;
 
 			// TODO: Heuristic that automatically elects rest if
 			// just enough to fill council.

src/multiwinner/qrange_stv.cc

@@ -144,7 +144,6 @@ int QRangeSTV::elect_next(size_t council_size, size_t num_candidates,
 	// i.e...
 
 	double p_y = quota / count_quad[winner];
-	double verify = 0;
 
 	election_t::iterator pos = altered_ballots.begin();
 
@@ -165,7 +164,6 @@ int QRangeSTV::elect_next(size_t council_size, size_t num_candidates,
 			pos = altered_ballots.erase(pos);
 		} else {
 			pos->set_weight(std::max(0.0, pos->get_weight() - subtr));
-			verify += pos->get_weight() * winner_score;
 			++pos;
 		}
 	}

src/tools/tools.cc

@@ -457,7 +457,12 @@ std::vector<std::vector<bool> > power_set(
 		}
 	}
 
-	assert(power_set_out.size() == (1ULL << num_hopefuls));
+	// Can't use assert because then clang will complain when making
+	// a Release build.
+	if (power_set_out.size() != (1ULL << num_hopefuls)) {
+		throw std::logic_error("power_set: output set is of the wrong size! "
+			"This is a bug.");
+	}
 
 	return power_set_out;
 }

src/tools/tools.h

@@ -9,6 +9,8 @@
 #include <vector>
 #include <map>
 
+typedef ptrdiff_t ssize_t;	/* ssize_t is not part of the C standard */
+
 const double PI = 4 * atan(1);
 
 // Transforms parameters of 0 1 2 ... skip skip+1 ... into