systemc: Add deprecated default time unit management functions.

Having default time units is deprecated, and so are the functions that
manage them.

Change-Id: Ie21f9a5fca9868dd4f0adcd9f32c568fbec1fa72
Reviewed-on: https://gem5-review.googlesource.com/11270
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/core/sc_time.cc

@@ -229,4 +229,17 @@ sc_max_time()
     return *(const sc_time *)nullptr;
 }
 
+void
+sc_set_default_time_unit(double, sc_time_unit)
+{
+    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
+}
+
+sc_time
+sc_get_default_time_unit()
+{
+    warn("%s not implemented.\n", __PRETTY_FUNCTION__);
+    return *(sc_time *)nullptr;
+}
+
 } // namespace sc_core

src/systemc/ext/core/_using.hh

@@ -140,5 +140,7 @@ using sc_core::SC_ZERO_TIME;
 using sc_core::sc_set_time_resolution;
 using sc_core::sc_get_time_resolution;
 using sc_core::sc_max_time;
+using sc_core::sc_get_default_time_unit;
+using sc_core::sc_set_default_time_unit;
 
 #endif  //__SYSTEMC_EXT_CORE__USING_HH__

src/systemc/ext/core/sc_time.hh

@@ -93,6 +93,10 @@ void sc_set_time_resolution(double, sc_time_unit);
 sc_time sc_get_time_resolution();
 const sc_time &sc_max_time();
 
+// Deprecated
+void sc_set_default_time_unit(double, sc_time_unit);
+sc_time sc_get_default_time_unit();
+
 } // namespace sc_core
 
 #endif  //__SYSTEMC_EXT_CORE_SC_TIME_HH__