Allow NO_SYSTEM_FROM_IMPORTED on imported INTERFACE libraries

Imported INTERFACE libraries can specify include directories via
`INTERFACE_INCLUDE_DIRECTORIES` so the default behavior of treating them
as system include directories applies.  Allow users to turn this off by
setting `NO_SYSTEM_FROM_IMPORTED` on such targets.

Closes: #16443

Help/manual/cmake-buildsystem.7.rst

@@ -964,6 +964,7 @@ are:
 * ``EXPORT_NAME``
 * ``IMPORTED``
 * ``NAME``
+* ``NO_SYSTEM_FROM_IMPORTED``
 * Properties matching ``IMPORTED_LIBNAME_*``
 * Properties matching ``MAP_IMPORTED_CONFIG_*``
 

Help/release/dev/imported-interface-no-system.rst

@@ -0,0 +1,5 @@
+imported-interface-no-system
+----------------------------
+
+* The :prop_tgt:`NO_SYSTEM_FROM_IMPORTED` target property is now supported
+  on :ref:`Imported <Imported Targets>` :ref:`Interface Libraries`.

Source/cmTarget.cxx

@@ -253,7 +253,6 @@ cmTarget::cmTarget(std::string const& name, cmStateEnums::TargetType type,
     this->SetPropertyDefault("WIN32_EXECUTABLE", CM_NULLPTR);
     this->SetPropertyDefault("MACOSX_BUNDLE", CM_NULLPTR);
     this->SetPropertyDefault("MACOSX_RPATH", CM_NULLPTR);
-    this->SetPropertyDefault("NO_SYSTEM_FROM_IMPORTED", CM_NULLPTR);
     this->SetPropertyDefault("C_CLANG_TIDY", CM_NULLPTR);
     this->SetPropertyDefault("C_COMPILER_LAUNCHER", CM_NULLPTR);
     this->SetPropertyDefault("C_INCLUDE_WHAT_YOU_USE", CM_NULLPTR);
@@ -271,6 +270,10 @@ cmTarget::cmTarget(std::string const& name, cmStateEnums::TargetType type,
     this->SetPropertyDefault("LINK_SEARCH_END_STATIC", CM_NULLPTR);
   }
 
+  if (this->GetType() != cmStateEnums::UTILITY) {
+    this->SetPropertyDefault("NO_SYSTEM_FROM_IMPORTED", CM_NULLPTR);
+  }
+
   // Collect the set of configuration types.
   std::vector<std::string> configNames;
   mf->GetConfigurations(configNames);

Source/cmTargetPropertyComputer.cxx

@@ -66,6 +66,7 @@ bool cmTargetPropertyComputer::WhiteListedInterfaceProperty(
   }
 
   if (prop == "IMPORTED_CONFIGURATIONS" || prop == "IMPORTED_LIBNAME" ||
+      prop == "NO_SYSTEM_FROM_IMPORTED" ||
       cmHasLiteralPrefix(prop, "IMPORTED_LIBNAME_") ||
       cmHasLiteralPrefix(prop, "MAP_IMPORTED_CONFIG_")) {
     return true;

Tests/InterfaceLibrary/CMakeLists.txt

@@ -64,6 +64,7 @@ target_link_libraries(iface_whitelist INTERFACE $<$<BOOL:$<TARGET_PROPERTY:CUSTO
 add_executable(exec_whitelist dummy.cpp)
 target_link_libraries(exec_whitelist iface_whitelist)
 
+set(CMAKE_NO_SYSTEM_FROM_IMPORTED 1)
 add_library(iface_imported INTERFACE IMPORTED)
 set_property(TARGET iface_imported PROPERTY
   INTERFACE_COMPILE_DEFINITIONS