Fix TrxId_Interval comparison operators to be const for macOS compilation

include/proxysql_gtid.h

@@ -28,9 +28,9 @@ class TrxId_Interval {
 		const bool merge(const TrxId_Interval& other);
 
 		const int cmp(const TrxId_Interval& other);
-		const bool operator<(const TrxId_Interval& other);
-		const bool operator==(const TrxId_Interval& other);
-		const bool operator!=(const TrxId_Interval& other);
+bool operator<(const TrxId_Interval& other) const;
+bool operator==(const TrxId_Interval& other) const;
+bool operator!=(const TrxId_Interval& other) const;
 };
 
 // Encapsulates a map of UUID -> trxid intervals.

lib/proxysql_gtid.cpp

@@ -158,15 +158,15 @@ const int TrxId_Interval::cmp(const TrxId_Interval& other) {
 	return 0;
 }
 
-const bool TrxId_Interval::operator<(const TrxId_Interval& other) {
+bool TrxId_Interval::operator<(const TrxId_Interval& other) const {
 	return cmp(other) == -1;
 }
 
-const bool TrxId_Interval::operator==(const TrxId_Interval& other) {
+bool TrxId_Interval::operator==(const TrxId_Interval& other) const {
 	return cmp(other) == 0;
 }
 
-const bool TrxId_Interval::operator!=(const TrxId_Interval& other) {
+bool TrxId_Interval::operator!=(const TrxId_Interval& other) const {
 	return cmp(other) != 0;
 }