Xcode: Restore support for standalone IMPORTED_LOCATION_<CONFIG>

In commit 878ae03832 (macOS: IMPORTED framework: Honor SYSTEM target
property in all cases, 2023-08-27, v3.28.0-rc1~162^2) we broke support
for `IMPORTED_LOCATION_<CONFIG>` without `IMPORTED_CONFIGURATIONS`.
Previously it worked if the importing project's configurations match the
set of `IMPORTED_LOCATION_<CONFIG>` properties set.  Fix that case.

Fixes: #25506
Issue: #25515

Source/cmGeneratorTarget.cxx

@@ -8762,11 +8762,23 @@ bool cmGeneratorTarget::IsFrameworkOnApple() const
 bool cmGeneratorTarget::IsImportedFrameworkFolderOnApple(
   const std::string& config) const
 {
-  return this->IsApple() && this->IsImported() &&
-    (this->GetType() == cmStateEnums::STATIC_LIBRARY ||
-     this->GetType() == cmStateEnums::SHARED_LIBRARY ||
-     this->GetType() == cmStateEnums::UNKNOWN_LIBRARY) &&
-    cmSystemTools::IsPathToFramework(this->GetLocation(config));
+  if (this->IsApple() && this->IsImported() &&
+      (this->GetType() == cmStateEnums::STATIC_LIBRARY ||
+       this->GetType() == cmStateEnums::SHARED_LIBRARY ||
+       this->GetType() == cmStateEnums::UNKNOWN_LIBRARY)) {
+    std::string cfg = config;
+    if (cfg.empty() && this->GetGlobalGenerator()->IsXcode()) {
+      // FIXME(#25515): Remove the need for this workaround.
+      // The Xcode generator queries include directories without any
+      // specific configuration.  Pick one in case this target does
+      // not set either IMPORTED_LOCATION or IMPORTED_CONFIGURATIONS.
+      cfg =
+        this->Makefile->GetGeneratorConfigs(cmMakefile::IncludeEmptyConfig)[0];
+    }
+    return cmSystemTools::IsPathToFramework(this->GetLocation(cfg));
+  }
+
+  return false;
 }
 
 bool cmGeneratorTarget::IsAppBundleOnApple() const

Tests/RunCMake/target_link_libraries/ImportedTargetPerConfig.cmake

@@ -0,0 +1,27 @@
+enable_language(C)
+get_property(_isMultiConfig GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+if(NOT _isMultiConfig AND NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE "Debug")
+endif()
+
+add_library(StaticImported STATIC IMPORTED)
+
+# Test with no IMPORTED_CONFIGURATIONS, which works if the
+# imported target provides all exact-name configurations
+# built by this project.  See issue #25515.
+set_target_properties(StaticImported PROPERTIES
+  IMPORTED_LOCATION_DEBUG "a"
+  IMPORTED_LOCATION_RELEASE "b"
+  IMPORTED_LOCATION_MINSIZEREL "c"
+  IMPORTED_LOCATION_RELWITHDEBINFO "d"
+  )
+
+add_library(StaticLib STATIC empty.c)
+
+# The Xcode generator queries imported targets for system
+# include directories, but without any specific config.
+set_source_files_properties(empty.c PROPERTIES
+  INCLUDE_DIRECTORIES "${CMAKE_CURRENT_SOURCE_DIR}"
+  )
+
+target_link_libraries(StaticLib PRIVATE StaticImported)

Tests/RunCMake/target_link_libraries/RunCMakeTest.cmake

@@ -25,6 +25,7 @@ run_cmake(CMP0108-NEW-self-link)
 run_cmake(ImportedTarget)
 run_cmake(ImportedTargetStub)
 run_cmake(ImportedTargetFailure)
+run_cmake(ImportedTargetPerConfig)
 run_cmake(MixedSignature)
 run_cmake(Separate-PRIVATE-LINK_PRIVATE-uses)
 run_cmake(SharedDepNotTarget)