Fix compiler warnings by ensuring variable initialization

Author: Al2Klimov

lib/base/tcpsocket.cpp

@@ -32,8 +32,8 @@ void TcpSocket::Bind(const String& node, const String& service, int family)
 {
 	addrinfo hints;
 	addrinfo *result;
-	int error;
-	const char *func;
+	int error = 0;
+	const char *func = nullptr;
 
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = family;
@@ -126,8 +126,8 @@ void TcpSocket::Connect(const String& node, const String& service)
 {
 	addrinfo hints;
 	addrinfo *result;
-	int error;
-	const char *func;
+	int error = 0;
+	const char *func = nullptr;
 
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = AF_UNSPEC;

lib/icinga/legacytimeperiod.cpp

@@ -541,7 +541,7 @@ Dictionary::Ptr LegacyTimePeriod::FindNextSegment(const String& daydef, const St
 				ProcessTimeRanges(timeranges, &iter, segments);
 
 				Dictionary::Ptr bestSegment;
-				double bestBegin;
+				double bestBegin = 0;
 
 				ObjectLock olock(segments);
 				for (Dictionary::Ptr segment : segments) {

tools/mkclass/class_lexer.ll

@@ -26,8 +26,8 @@ do {							\
 } while (0)
 
 struct lex_buf {
-	char *buf;
-	size_t size;
+	char *buf = NULL;
+	size_t size = 0;
 };
 
 static void lb_init(lex_buf *lb)