feat: iec80000 namespace marked as deprecated

src/systems/CMakeLists.txt

@@ -45,6 +45,7 @@ add_mp_units_module(
             include/mp-units/systems/hep.h
             include/mp-units/systems/iau.h
             include/mp-units/systems/iec.h
+            include/mp-units/systems/iec80000.h
             include/mp-units/systems/imperial.h
             include/mp-units/systems/international.h
             include/mp-units/systems/isq.h

src/systems/include/mp-units/systems/iec80000.h

@@ -0,0 +1,44 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#pragma once
+
+// IWYU pragma: begin_exports
+#include <mp-units/systems/iec.h>
+// IWYU pragma: end_exports
+
+namespace mp_units {
+
+MP_UNITS_EXPORT
+namespace [[deprecated("Use `mp_units::iec` namespace from iec.h instead")]] iec80000 {
+
+namespace [[deprecated("Use `mp_units::iec::unit_symbols` namespace from iec.h instead")]] unit_symbols {
+
+using namespace iec::unit_symbols;
+
+}
+
+using namespace iec;
+
+}  // namespace iec80000
+
+}  // namespace mp_units

src/systems/mp-units-systems.cpp

@@ -39,6 +39,7 @@ import std;
 #include <mp-units/systems/hep.h>
 #include <mp-units/systems/iau.h>
 #include <mp-units/systems/iec.h>
+#include <mp-units/systems/iec80000.h>
 #include <mp-units/systems/imperial.h>
 #include <mp-units/systems/international.h>
 #include <mp-units/systems/isq.h>