CORELIB: clock_utc() now returns always the UTC time in system clock representation.

- This is a breaking change on Windows and Linux with gcc >= 13.
  The leap seconds are not counted anymore. Thus, the annoying offset to the system time is gone.

Author: Florian Thake

Deprecation_and_Breaking_Changes.txt

@@ -3,6 +3,11 @@ TeaScript Breaking Changes in the actual release
 
     Changes in CoreLibrary functionality
     ------------------------------------
+    clock_utc() has a breaking change on Windows and Linux with gcc >= 13.
+    clock_utc() now returns always the UTC time in system clock representation.
+    On Windows and on Linux with GCC >= 13 this is a breaking change since the leap seconds are not counted anymore.
+    The previous wrong behavior resulted due to a misunderstanding of the underlying C++ API.
+    Now there isn't an annoying offset to the system clock time anymore.
 
 
     Changes on C++ API level
@@ -24,13 +29,6 @@ TeaScript list of deprecated parts
 =================================================
 
     The following deprecated parts have been finally removed from this release:
-    
-    exit( exit_code )
-    use either _exit( Any ) or the new _Exit statement instead.
-    A script will always have a result or NaV (Not A Value).
-
-    class Engine HasExitCode()/GetExitCode() and mExitCode
-    A script will always have a result or NaV (Not A Value).
 
 
     The following parts are now deprecated and will be removed in some future release:

Known_Issues.txt

@@ -21,9 +21,8 @@ NOTE: The numbers stay same, solved items will (usually) be removed in the next
     a total strong ordering will be performed and the values can be compared.
 
 
-8.) [PLATFORM: Linux with clang or gcc < 13]
-    CoreLibrary function clock_utc() will return UTC time _without_ leap seconds.
-    WORKAROUND: Use gcc >= 13 on Linux.
+8.) Solved! This issue was a misunderstanding of std::chrono::utc_clock.
+    Now, on all platforms clock_utc() returns the UTC time in system_clock representation.
 
 
 10.) [PLATFORM: any]

include/teascript/CoreLibrary.hpp

@@ -262,14 +262,11 @@ class CoreLibrary
 #endif
     }
 
-    /// gets the UTC time in fractional seconds (with leap seconds!).
+    /// gets the UTC time in fractional seconds.
     static double GetUTCTimeInSecs()
     {
-#if _MSC_VER || (!defined(__clang__) && __GNUC__ >= 13 ) // TODO: _LIBCPP_VERSION
-        auto const now = std::chrono::utc_clock::now(); // UTC with leap seconds.
-#else
+        // NOTE: std::chrono::utc_clock::now() is with(!) leap seconds. If use this for time representation it will be in the 'future' of the system clock!
         auto const now = std::chrono::system_clock::now(); // UTC without(!) leap seconds.
-#endif
         std::chrono::duration<double> const  timesecs = now - std::chrono::floor<std::chrono::days>( now );
         return timesecs.count();
     }
@@ -1940,7 +1937,7 @@ class CoreLibrary
                 tea_add_var( "clock", std::move( val ) ); // missing _ is intended for now.
             }
 
-            // clock_utc : f64 ( void ) --> gets the UTC time of the current day in (fractional) seconds as f64. (note: This UTC time is with leap seconds!)
+            // clock_utc : f64 ( void ) --> gets the UTC time of the current day in (fractional) seconds as f64.
             {
                 auto func = std::make_shared< LibraryFunction0< decltype(GetUTCTimeInSecs), double > >( &GetUTCTimeInSecs );
                 ValueObject val{std::move( func ), cfg_mutable};